Before You Construct a Water Well
Before You Construct
a Water Well
Facts a homeowner should know
Report 68-3
(First Revision 1972)
(Second Revision 1975)
(Third Revision 1981)
(Fourth Revision 1990)
(Fifth Revision 1997)
(Sixth Revision 2001)
(Seventh Revision 2004)
This document is also available on the web at: http://www.gov.ns.ca/enla/water
Environment and Labour
Halifax, Nova Scotia
2004
Preface
The cost of a well is usually small in comparison to
a house itself, but a home is worth little without a
good water supply. This booklet has been prepared
for prospective homeowners and others who may
have to have a well
constructed. The more
familiar you are with the
information in this
booklet, the more likely
you are to be satisfied
with your well and with
your home.
Nova Scotia Department of Environment
and Labour administers the Well
Construction Regulations. A list of
regional offices is provided for your
convenience at the end of this booklet.
Staff will be happy to provide general
information or to answer specific
questions regarding wells, water supply
potential, and the Regulations.
Table of Contents
A Water Supply in Your Home
What is Groundwater?
How Does Groundwater Occur in Nova Scotia?
1
2
Planning A Water Supply
Why Should I Have a Water Well Constructed Before I Build?
Where Do I Obtain Background Information for My Area?
How Much Water is Enough?
Where Should My Well Be Located?
3
4
7
8
Contracting The Job
How Do I Select A Water Well Contractor?
What Items Should Be Covered In The Contract?
Final Well Inspection
9
9
10
Components Of A Water Supply System
The Well
What is a Drilled Well?
What is a Dug Well?
How Long Should Well Yield Tests Be?
The Pump
How do I Select a Pump?
How do I Select a Pump Installer?
The Water Storage (Pressure) Tank
The Distribution System
The Treatment System
12
12
14
15
16
16
16
18
19
19
Water Quality
Why Should I Test?
What is Bacterial Quality
How Do I Test for Bacteria?
What Do The Results Mean?
What is Chemical Quality
How Do I Test for Chemical Quality?
What Do The Results Mean?
Water Treatment
20
20
20
21
23
23
24
26
Well Maintenance
How Often Should I Check Water Quality?
How Can I Protect my Water Supply for the Future?
27
27
Summary
28
References
29
Appendix 1
Disinfection of Water Wells by Chlorination
How do I Disinfect my Well?
Sampling After Disinfection
Final Notes
30
30
31
31
Appendix 2
Volume of Water in Wells
32
Nova Scotia Environment and Labour
Regional Offices
33
Notes or Sketches
34
Sample Drilled Well Contract
35
List of Figures
1. The Hydrologic Cycle
2. Groundwater Regions of Nova Scotia
3. Dry Shallow Wells in Subdivisions
4. Problems Encountered in Drilled Well Construction
5. Drilled Well Report
6. Dug Well Report
7. How Much is Enough?
8. Example of a Complete Water System
9. Common Defects of Well Construction with Remedies
10. Cross Section of a Typical Dug Well
11. Pump Installation Report
1
2
3
4
5
6
7
11
13
14
17
List Of Tables
1. Guidelines for Selected Chemical Parameters
2. Common Water Quality Problems and Possible Solutions
24
26
A Water Supply
in your Home
Water is the basis of life. You cannot survive without
it. In the past, there was little difficulty in finding
sufficient water for the limited household needs.
However, indoor plumbing and automatic appliances
place much greater demands on water supply today.
As a conservative estimate, a home will need in the
order of 340 litres (75 imperial gallons) per person
per day to meet all these needs.
A household needs not only enough water, but also
water that has good bacterial and chemical quality.
About half of Nova Scotians rely on groundwater for
water supply. The most common water supply for
the home that is not served by a public system is a
drilled well. In rural areas, three quarters of new
home water supplies are derived from drilled wells,
the remainder primarily from dug wells. Springs,
cisterns and surface water serve a very small
number of homes.
What is Groundwater?
Groundwater is water that is found in pore spaces
in the soil or in cracks or pores in the rock.
Groundwater begins as rain or snowmelt
(precipitation). This water can follow three main
paths:
• Some evaporates from the ground and open
water surfaces, or is ‘breathed’ out (transpired) by
vegetation and returns to the atmosphere where
it can again form clouds, rain and snow and
replenish the earth.
• Some runs off into streams or lakes or the ocean,
called surface water runoff.
• Some infiltrates into the ground. There, it follows
various routes (flowpaths) and can discharge to
the ground surface as springs, discharge into
surface water, or recharge groundwater deeper in
the earth. As groundwater moves through the
ground, it dissolves some of the minerals that it
contacts. These dissolved minerals give water its
chemical character or quality.
Precipitation
Transpiration
Ru
no
ff
Recharge
Water Table
Evaporation
Lake
Aquifer
Stream
Ocean
Figure 1 The hydrologic cycle, or water cycle. This cycle involves the circulation of water between
land, atmosphere, and ocean.
1
How Does Groundwater Occur in
Nova Scotia?
Groundwater is found in aquifers in the bedrock or
in the material above the bedrock. An aquifer is a
water-bearing permeable formation that will yield
water in a usable quantity to a well.
How much water a drilled well yields depends on
the type of bedrock, type of overburden or surficial
material (the geologic material above the bedrock),
well depth, and number of fractures (cracks) or
permeable layers encountered during drilling. The
bedrock aquifer generally consists of three main
rock types:
• igneous and metamorphic rocks such as slate,
quartzite and granite, which yield water mainly
from fractures
• sedimentary rocks such as sandstone, shale and
conglomerate, which yield water from spaces
between the grains and from fractures
• carbonate and evaporite rocks such as limestone
and gypsum, which yield water mainly from
fractures and cavities.
In most places in Nova Scotia, the overburden
above the bedrock is made up of glacial till, sandy
to clayey in composition, depending on the nature
of the local bedrock. Its thickness varies widely with
location, but generally ranges from 0 to 10 metres
(0 to 33 feet) and averages 6 m (20 ft). Dug wells
obtain water from this material or from the contact
zone between the surficial material and upper
weathered bedrock. Because till is generally low in
water yield, dug wells are usually constructed of
90 cm (3 foot) diameter crocks that can store large
amounts of water.
In some places, the overburden consists of
permeable sand and gravel deposits that are
saturated with water. Here, dug wells or screened
drilled wells may produce relatively good yields.
Such deposits occur along some of the major river
systems, the most extensive on the mainland being
in the Annapolis and Musquodoboit Valleys.
Figure 2 shows how these rock types are distributed
in Nova Scotia.
2
Figure 2 Groundwater Regions of Nova Scotia (Simplified from Water Resources Map, NSDOE, 1985)
Planning a Water Supply
Before you build your house or drill or dig your well,
plan your water supply: a house is worth little
without an adequate supply of good-quality water,
which may be found where you had hoped to place
the front steps!
To plan your water supply, find out what type of
material lies under the ground, how much water you
will need, and where the well should be constructed
to provide the best water supply
and meet regulations.
Why Should I Have a Water Well
Constructed Before I Build?
When you drill a well, you are actually exploring to
determine the quantity and quality of water
available. Totally ‘dry’ holes are uncommon, but lowyielding wells are more common than you may
realize. Some causes of low yield include low natural
or seasonal water table, interference with other wells
(for example in subdivisions), and geologic
conditions, as shown in Figure 3. In addition, good
quality water may be difficult to obtain in some areas
due to natural causes such as salt deposits and
closeness to the ocean. Occasionally
problems may arise with well construction,
as shown in Figure 4.
Have the well
constructed before
you build!
If problems arise, the cost to repair them is
less if you construct the well first, because
only the cost of the well is involved. Also, if
a second well must be dug or drilled, there is more
likely to be sufficient space on the property if the
house is not already there. Too many homes have
inadequate water supplies because the property
owner did not have a well constructed before the
home was built.
Figure 3 Dry Shallow Wells in Subdivisions
3
An expensive house with a poor well is a poor
investment; resale value will be lower. It may be very
costly to ensure an adequate supply of good-quality
water. It is better to have a well constructed and
assess the quantity and quality of the water supply
before you build a house. Also, in areas where a
usable water supply from drilled wells is
questionable, it is better to obtain an option on the
property with permission to have a well constructed
first. Following such a procedure may save you from
a bad investment.
Where Do I Obtain Background
Information for My Area?
The type of material beneath the ground surface in
your area (geology) can tell you how successful you
may be in obtaining a suitable water supply from a
well. In many areas of the province, groundwater
conditions have been examined and information can
be obtained from local well contractors, the nearest
Department of Environment and Labour Regional
Office (listed on page 33 of this booklet), and
neighbours.
4
• Local well contractors. Drawing on their
experience in the area, contractors can supply
information on the probable depth of the well,
and possible quantity and quality of water that
can be expected.
• Department of Environment and Labour.
Information on geology, general information on
the water supply potential for the area, and well
records for other drilled and dug wells in the
immediate vicinity are available. Well contractors
are required to file a standardized well report for
each well constructed (Figures 5 and 6). The
report includes information on well location,
depth, type and thickness of bedrock and surface
materials, quantity of water, and quality (e.g.,
sulfurous, salty, clear). An average of 3000
reports per year are entered into a computer
database.
• Nearby homeowners. Ask them about their
water quantity and quality.
Figure 4 Problems Encountered in Drilled Well Construction
Figure 5 Drilled Well Report
5
6
Figure 6 Dug Well Report
How Much Water is Enough?
‘Enough’ water means sufficient quantity to meet the
following needs:
• Everyday use: drinking, cooking, and all the
luxuries of inside plumbing. ‘Plumbing’ includes
toilets, bathtubs, showers,
automatic washers,
dishwashers, and many
other water-using
automatic appliances.
• Seasonal use: lawn and
garden watering, car
washing, and swimming
pool.
• Other special uses:
animal watering, crop
irrigation, water treatment devices which require
backwashing.
• Fire protection: this is a special need for which
a home seldom depends on a well. The local fire
department usually has access to large quantities
of water from ponds or surface water.
A day’s water use may be concentrated into a
period of one to two hours, often in different areas
of the house at the same time (laundry, bathroom,
lawn). The water supply system must be able to
meet this type of peak demand. Canada Mortgage
and Housing Corporation require
18 litres per minute (4 gallons per
minute) for one hour, and the
ability to reproduce this yield 24
hours later, before they will
approve a mortgage loan. Where
individual wells produce less than
this amount, at least 900 litres
(200 gallons) of cold water
storage must be provided.
A conservative estimate is that
a home will need about 680 to
1360 litres (150 to 300
gallons) per day for two to four
people to meet average needs.
Three factors must be considered when determining
how much is ‘enough’:
• Flow Rate: continuous rate of yield for well.
• Size of Well: diameter and depth of well.
• Static Level: level at which water stands in a
well when no water is being pumped from the
well.
Examples of wells which will give
adequate supplies for average households.
76 m (250 ft.)
61 m (200 ft.)
15 m (50 ft.)
Water Level
3m (10’)
46 m (150 ft.)
152 mm (6”)
30 m (100 ft.)
Diameter
18 litres/min.
(4 gal/min)
11 litres/min.
(2.5 gal/min)
7 litres/min.
(1.5 gal/min)
4.5 litres/min.
(1 gal/min)
It is recommended that Dept. of Environment and Labour
be consulted before drilling beyond 91 m (300 ft.).
2.3 litres/min.
(0.5 gal/min)
Figure 7 The question “How much is enough?” depends on a combination of factors such as well yield,
well diameter and depth, and static water level (natural water level with no pumping). Whatever
the quantity available, water conservation is good practice, cutting energy cost and load on the
sewer system and making the best use of low-yield wells. Appendix 2 shows how to calculate
the volume of water stored in your well.
7
In addition to providing for regular household use,
wells sometimes supply water for heating and cooling
purposes. Some energy-conscious homeowners
install groundwater heat pumps, which extract and
concentrate heat energy from water and make it
available for heating or cooling purposes. Groundwater
is a good source for heating or cooling because below
a depth of 6.1 m (20 ft) its temperature is
approximately constant at between 7 and 10°C.
When the household supply well is also being used to
provide water for a groundwater source heat pump,
the well should be able to deliver between 27 and 55
litres (6 and 12 gallons) per minute. This discharge
rate must be added to the peak demand allowance
required for the home. Some homes use a more
complicated two-well system for heat pump purposes.
Be careful not to overlook items that you may take
for granted in a city with a good water supply. A
home with its own water system and pump can offer
the same conveniences, provided the quantity and
quality of the water are adequate.
Where Should My Well Be Located?
The actual location of the well on your property will
often be determined by factors other than the
geology. Land surface features such as steep slopes
and poorly drained areas are considerations in the
location of the well and building. Whenever possible,
wells should be located at
higher elevations than the
surrounding areas, to
decrease the potential for
contamination.
• Where surface water runoff will pass over or near
the opening of the well, the area immediately
surrounding the well shall be filled with clay or
clean earth for a distance of at least 4.5 m (15 ft)
in all directions from the well and graded to an
elevation of at least 610 mm (2 ft) above the
highest known surface water level.
The well should be located and maintained so that it
is accessible for cleaning, treatment, repair, testing,
inspection and other activities which may be
necessary over time.
• The top of a well must not be located within the
basement or under a building having no
basement unless special provisions are made for
servicing and repairing the well.
The well must
be accessible.
8
The following minimal distances must be
maintained, unless other local codes or regulations
(such as On-site Sewage Disposal Systems
Regulations) are more stringent:
Boundary or
Source of Pollution
Distance
Cesspool (receiving raw sewage)
61 m (200 ft)
Seepage (leaching pit), filter bed,
soil absorption field, earth pit,
privy or similar disposal unit
• From a drilled well
• From a dug well
15.2 m (50 ft)
30.5 m (100 ft)
Septic tank, concrete vault privy,
sewer of tightly joined tile or
equivalent material or sewerconnected foundation drain
• From a drilled well
• From a dug well
15.2 m (50 ft)
30.5 m (100 ft)
Sewer of cast iron with leaded
or approved mechanical joints,
independent clear water drain,
or cistern
3 m (10 ft)
Pumphouse floor drain, cast
iron with leaded joints,
draining to ground surface
610 mm (2 ft)
Vertical extension of the
centre line of the well from
any projection of a building
1.6 m (5.2 ft)
Property boundary
1.5 m (5 ft)
Outer boundary of any road
or public highway as defined
in the Public Highways Act
6.1 m (20 ft)
Landfill, garbage dump or other
source of contamination (if
written approval is granted for
well construction)
61 m (200 ft)
Contracting the Job
How Do I Select A Water Well Contractor?
Under the Well Construction Regulations, all
persons constructing or repairing water wells must
have a certificate of qualification from the
Department of Environment and Labour. The
certificate is renewable annually.
Nova Scotia has approximately 50 certified drilled
well and 250 certified dug well contractors. Most
operate within a one- to three-county radius.
Experienced contractors who have worked in the
area will be familiar with local conditions.
Prior to selecting a water well contractor for the job,
it is a good idea to obtain information from and
about several contractors. Check for the following:
✓ Does he have a valid certificate of qualification
from Department of Environment and Labour?
✓ Does he regularly submit well logs as required?
✓ Does he have adequate equipment in good
condition to do the job?
✓ Does he have adequate liability and worker’s
compensation insurance to protect you?
✓ Is he familiar with
applicable health and
safety codes?
✓ What is the contractor’s
reputation with previous
customers?
✓ Will he furnish a written
contract, specifying the
terms and conditions for
the job?
Once the contractor is selected, keep in mind the
following principles:
• Trust the contractor’s judgement in solving
unforeseen difficulties that may come up and
discuss unforeseen costs.
• If original construction plans must be changed,
discuss the options with the contractor and/or
Department of Environment and Labour.
• Don’t expect the contractor to work for nothing if
the well does not fulfill expectations.
What Items Should Be Covered In
The Contract?
Unless you know what each contractor will do for his
specified price, you cannot compare offers and
decide which one to hire. A low lump sum may
result in an unsatisfactory job if the workmanship
and materials are poor. To ensure that you are
satisfied and to protect yourself in case of court
action, you should have a written contract. The
contract is protection for both you and the
contractor.
Some contractors rely on verbal or handwritten
agreements, others have a standard contract form,
specifying in detail the work
to be done, prices, and
terms. A sample contract is
shown at the back of this
booklet. For a drilled well,
the contract may include
items such as:
• liability insurance
coverage held by both
the owner and the
contractor
• a statement that all work
is to comply with local
and provincial
regulations and codes
All persons constructing or
repairing water wells must have a
certificate of qualification.
The contractor must work with
geologic conditions as they exist
and cannot guarantee quantity or
quality of water. Low yield and poor
water quality may be due to
natural conditions in the area.
9
• the diameter and wall thickness of the casing to
be used
• the type of well development and yield evaluation
procedures to be used
• the type of screen to be installed, where needed
• the type of well cap or seal to be provided
• the disinfection procedure
• the cleanup after drilling which includes all
material abandoned without authorization at a
drill site except drill cuttings and wastewater
• an anticipated date for start of drilling
• a guarantee of materials and workmanship. The
contract should specify that the contractor will
return to do or to correct the initial work if
necessary
• costs: An itemized list of charges is better than a
lump sum. The list could include:
- cost of drilling per metre (foot)
- cost of casing per metre (foot)
- cost of other materials, such as drive shoe,
grout, well cap
- cost of other operations, such as grouting,
developing (if longer than an hour, such as in
screened wells), test pumping, disinfection
- cost of drilling deeper and/or a second well, if
required to ensure an adequate water supply
- cost of abandonment should it prove
necessary (for example if salt water is
encountered and another site must be
selected)
- what costs are not included in the
specifications
10
Final Well Inspection
After the well has been constructed and before the
contractor removes his equipment from the site, you
should inspect the well. Here is a list of items to
check:
• Well depth. This is easily done by tying a weight
on a tape. Verify the measurement against the
well construction report made out by the
contractor.
• Well yield. Ask the contractor at how many litres
(gallons) per minute the well was tested, what
distance the water level dropped during the test,
and how quickly the water level recovered after
the test.
• Well cap. Ensure that the well is capped and
secure and that the cap is at least 152 mm (6 in)
above ground level.
• Disinfection. Ask the contractor if the well was
disinfected.
• Well construction record. Make certain that you
will receive your copy of the well record. The
contractor is required to deliver copies of the
record to the owner and to Department of
Environment and Labour within a month of
drilling, and to keep a record for himself for two
years. It would be advisable for you to keep your
well record with your house deed so that the
information is passed on to future owners.
report consists of the components between the
source and you, the end user: well, pump, water
storage (pressure) tank, distribution system, and
treatment system if necessary. Figure 8 shows a
typical complete drilled well system installed with
a submersible pump.
Components of a
Water Supply System
Once a water source is established, and a pump
contractor is selected, the water supply system
can be installed. The system as referred to in this
23
wall
13
9
22
15
11
ground surface
12
10
14
21
6
frost line
18
8
17 16
20
19
well casing
foundation
footing
surficial material
Legend
1 submersible pump
2 pump intake
3 check valve and fitting
4 torque arrestor
5 safety cable or rope
6 electric cable
7 electric cable taped or
tied to drop pipe every
3 m (10 ft)
8 pitless adaptor
9 vermin-proof vented
well cap
10 electrical cable in
conduit
11 pump control box and
safety switch
bedrock
drive shoe
12
13
14
15
16
17
18
19
20
21
22
lightning arrestor
power disconnect
pressure switch
pressure tank
sampling tap/drain valve
relief valve
pressure gauge
check valve (optional)
tank ‘tee’
isolation valve
discharge line to
treatment (if applicable)
and house
23 from electrical panel
Figure 8 Example of a Complete Water System (not to scale)
7
open hole
6
5
4
3
2
1
11
The Well
The well must be constructed according to specific
regulatory requirements of the Well Construction
Regulations established under Section 110 of the
Environment Act.
What is a Drilled Well?
A drilled well consists of a hole bored into the
aquifer, with the upper part lined with casing, usually
steel. The casing prevents the collapse of the
borehole walls and, along with a drive shoe or
grout seal, helps prevent surface or subsurface
contaminants from entering the water supply. The
casing also provides a housing for the pumping
mechanism and for the pipe, usually plastic, that
moves water from the pump to the surface.
A minimum of 152 mm (6 in) casing diameter
is required to ensure ease of servicing (e.g.,
deepening or installing liner casing or packer) and
installing proper pumping equipment. The casing
must meet certain specifications, since substandard
pipe does not have sufficient strength to withstand
driving without potential damage to the joints. Such
damage may allow contaminated shallow or surface
water to enter the well.
The casing must also have a drive shoe attached to
the bottom to prevent damage during driving and to
make a good seal with the formation. In some
applications, a grout seal of cement or bentonite
may also be recommended to prevent
contamination.
Below the casing, the lower portion of the borehole
is the intake through which water enters the well
from the aquifer. The intake may be an open hole in
solid bedrock, or it may be screened and gravelpacked, depending upon the geologic conditions.
Once the well is completed, it is bailed or pumped to
‘develop’ the aquifer and determine the yield. Many
aquifers need further work after drilling to remove
fine material remaining from the drilling process so
that water can more
readily enter the well.
Possible development
methods include
compressed air
(‘blowing’), bailing,
jetting, surging, or
pumping. The quantity
of water (yield test) is
usually measured during development. The
minimum test time required is one hour.
Construct the well
according to the
Well Construction
Regulations.
After proper disinfection, the well is capped to
provide sanitary protection until it is hooked into the
user’s system. The cap requires an air vent. The
purpose of the vent is to equalize the air pressure
between the inside of the casing and the
atmosphere, and to release unpleasant or explosive
lighter-than-air gases. If such gases are present and
the well is enclosed in a building or confined space,
the air vent should always be extended to the
outside atmosphere. The vent pipe must be shielded
and screened to prevent the entry of foreign material
such as insects into the well. Earwigs, for example,
can cause a high bacterial count.
If drilling produces poor-quality water, the water can
be sealed off. One method is to install additional
casing or liner inside the original casing and grout it
in place. Figure 9 shows some common defects in
well construction and illustrates how grouting or
sealing the annular space can be a solution.
12
If the water quality remains unsatisfactory, or if
construction defects cannot be remedied, the well
must be abandoned and completely sealed to
prevent cross-contamination between aquifers.
Abandonment of, or changes to, a well must be
recorded on the well contractor’s report filed with
Department of Environment and Labour.
Regulatory requirements for drilled wells include the
following specifications, although variances may be
granted under some conditions.
• The casing must be of new material, with a
nominal inside diameter of at least 152 mm (6
in), minimum length 6.1 m (20 ft), and must
extend at least 152 mm (6 in) above the ground
surface upon completion. It must be of standard
weight and wall thickness according to ASTM
(American Society for Testing of Materials)
Standard A589 (type IV, grade B) or A53 (type E,
grade B) for carbon steel casing and F480 for
thermoplastic well casing. Steel casing in Nova
Scotia is normally welded, and has a minimum
wall thickness of 4.7 mm (0.185 in).
• The casing must have a drive shoe attached to
the bottom. Grouting is not required, but if there
is a potential for contamination, the casing should
have a cement or bentonite grout seal at least
25 mm (1 in) thick.
• Upon completion of the well, all debris should be
removed and the well should be disinfected.
• The well must be sealed or capped until a pump
is installed. The minimum requirement is a
vermin-proof, vented, pitless well cap. Such a
cap is fitted with a rubber gasket for sealing and
attaching to the top of the casing. A screened
vent at least 12 mm (0.5 in) diameter is present
in the cap so only atmospheric air can enter the
well. A sealing device in the cap allows watertight passage of power cables to the well.
If there are any drilled wells on your property which
are not being used or maintained for present or
future use, the Well Construction Regulations
require that they must be properly abandoned, in a
manner approved by a Department of Environment
and Labour Inspector. Such wells may be an avenue
for groundwater contamination and/or a safety
hazard. For further information, contact your local
Department Office (see list on page 33).
Figure 9 Common Defects of Well Construction and Remedies Note that grouting can solve many problems.
13
What is a Dug Well?
A dug well consists of an excavation (usually with a
backhoe or excavator) into the aquifer, and is lined
with concrete crocks. The crocks prevent the
collapse of the excavated walls and, along with an
apron and seal, exclude surface contaminants from
entering the water supply.
In a dug well, the hole is either lined with crocks to
the bottom, or crocks at the top and rocks at the
bottom, and the crocks are backfilled as described
below.
14
Figure 10 Cross Section of a Typical Dug Well
Once the well is completed, it is bailed with the
backhoe or excavator bucket or pumped to develop
the aquifer and determine the yield. After proper
disinfection, the well is capped or sealed to provide
sanitary protection until it is hooked into the user’s
system.
Figure 10 illustrates a typical dug well construction.
Regulatory requirements for dug wells include the
following specifications, although variances may be
granted under some conditions.
• The well casing consists of groove joint, precast
concrete rings. It extends at least 152 mm (6 in)
above the land surface, and drainage is away
from the well. At least the top 1.8 m (6 ft) of
casing consists of concrete rings, or poured
reinforced concrete or brick lining.
• A concrete apron at least 152 mm (6 in) thick is
constructed around the well below the frost line,
extending a minimum distance of 914 mm (3 ft)
from the perimeter of the well. Minimum slope of
the apron is 21 mm/m (0.25 in/ft). Above this
apron, all joints in the casing are made
watertight, either with sand and cement mortar
mix, or with a certified non-toxic flexible sealing
compound.
• The annular space (space between the well
casing and the geologic material around it) from
the bottom of the well to the apron is filled with
clean washed gravel, sand, crushed rock, or
small boulders. From above the apron to the land
surface is backfilled with cement or bentonite
grout or equivalent commercial slurry, clay slurry,
or puddled clay to prevent the direct entry of
surface water into the well.
• Where a pump connection is made below
ground, the connection must be made watertight
with durable non-toxic sealing material. The pump
connection excavation is filled with cement or
bentonite grout or equivalent commercial slurry,
clay slurry, puddled clay, or native material (if
clayey), extending from the casing at least
305 mm (1 ft) outwards, and extending from the
bottom of the excavation to within 610 mm (2 ft)
of the land surface to prevent surface water entry.
• After the well is completed, any debris within and
around the well should be removed and the well
disinfected.
If there are any dug wells on your property which
are not being used or maintained for present or
future use, they must be properly abandoned, as
noted under drilled wells (page 13).
How Long Should Well Yield Tests Be?
Following construction of a well, the driller or digger
estimates the yield of the well. For water use for
other than a single residence, longer tests are
necessary to determine if the estimated yield is
sustainable when pumping for long periods of time.
Specific requirements include the following.
• Where a well is intended to supply water for
domestic purposes to a single residence with use
less than 23,000 litres (5000 gallons) per day, the
well contractor performs either a bail or air lift test
of not less than one hour’s duration or a pump
test of not less than six hours’ duration. Water
level recovery is observed and recorded as part
of the test.
• Where a well is intended to supply water for
domestic purposes to a single residence with use
greater than 23,000 litres (5000 gallons) per day,
a pump test of not less than 24 hours’ duration
must be carried out by a certified individual at the
well owner’s expense.
• Where a well is intended to supply water for any
other purposes, a pump test of 72 hours’ duration
must be carried out by a certified individual at the
well owner’s expense. For a public water supply,
additional wells for observation purposes may
also be required.
• Water level measurements must be made by a
certified individual before, during, and after any
pump test. Sufficient measurements of water
level recovery must be made after pumping stops
to establish the recovery curve.
The results of the tests, including analyses and
interpretations, must be reported to the Department
of Environment and Labour within 30 days of
completion of the test. The well contractor reports
the results of the preliminary yield test required for
all new wells. The well owner reports the information
in the case of wells where any additional testing is
required.
15
The Pump
How do I Select a Pump?
Once the well has been completed and developed
to produce clear water, a pump is necessary to
move the water from the well to the point of use.
Pumps that lift water by suction from depths of
7.6 m (25 ft) or less are called shallow well pumps.
Pumps that lift water from greater depths are called
deep well pumps. The most common types of deep
well pumps are submersible pumps, although deep
well jet pumps are still used.
The pump should have adequate capacity for
present and future uses. Generally, pump capacity
is equal to or slightly less than the safe yield of the
well so it will make use of the well’s potential but not
overpump it. A pump with a capacity greater than
the safe yield will draw the water level down in the
well too far, causing the system to pump air or lose
its prime. Continued lowering of the water level by
pumping may cause other difficulties in the well itself
(decrease in yield, cloudy water, sand in water). The
pump should also provide adequate pressure for the
present and future use, considering the possibility of
a lower water level in the well.
Generally, you will rely on a competent, certified
pump installer to select and install the pump (see
checklist below). Here are some considerations for
pump selection.
• Costs involved, including the pump itself, labour
to install it, materials (fittings, piping, accessories,
pitless adaptor, etc), operation (power plus
replacement parts).
• Power supply available, i.e., 125 versus 250 volt
service.
• Is sufficient space available to install the pump?
• Ease and cost of servicing the pump. Can it be
repaired in the field or in the dealer’s repair shop,
or does it have to go back to the factory?
• Will the pump dealer agree to install and service
the pump?
16
How do I Select a Pump Installer?
Under the Well Construction Regulations, all
persons installing, repairing, or modifying pumping
equipment in a well must have a certificate of
qualification from the Department of Environment
and Labour. The certificate is renewable annually.
There are about 600 certified pump installers in
Nova Scotia. The guidelines for hiring a pump
installer are similar to those for hiring a well
contractor. They are detailed on page 9, but, briefly,
you should check for the following:
✓ a valid certificate of qualification
✓ adequate equipment to do the job
✓ adequate liability and worker’s compensation
insurance
✓ history of submitting logs to the Department of
Environment and Labour
✓ familiarity with relevant health and safety codes
✓ references from previous jobs
The installer must assess the well and determine
depth and static water level. He must submit a
record for
each pump
installed or
repaired
(Figure 11).
All persons installing,
repairing, or modifying pumping
equipment in a well must have
a certificate of qualification.
Figure 11 Pump Installation Report
17
The Well Construction Regulations provide
specifications for pump installations. They are listed
here.
• An air vent must be present, with nominal inside
diameter at least 12 mm (0.5 in), that extends at
least 152 mm (6 in) above ground surface into
the open air. The open end must be shielded and
screened to prevent entry into the vent of any
solid or liquid substance into the well. A
regulation cap will provide such a vent. The
purpose of the vent was discussed earlier.
• Maintain a clearance of at least 12 mm (0.5 in)
between the pumping equipment and the
sidewall of the well.
• A new well and pumping or water distribution
equipment must be properly connected with a
pitless adaptor. The installation should take into
account possible corrosion of different metal
components.
• Any hand pump mounted on well casing or pump
mounting sleeve must be sealed to prevent the
entry of any solid or liquid substance into the
well.
• A sampling port or tap must be available between
the well and any water treatment device for
drawing raw water.
• The installation must meet the building code of
the municipality where the pump is to be
installed. The minimum requirement is
compliance with the National Plumbing Code of
Canada.
• After completion of the work, debris must be
removed from within and around the well and the
well disinfected.
New household systems must use a pitless adaptor.
Pitless adaptors are devices designed for
attachment to the well casing below the frostline and
provide a watertight seal where the water line
passes through the wall casing (Figure 8). They
have three main functions:
• to prevent entrance of contamination into a well
• to conduct the water from the well to the home
• to provide access to the pumping equipment
within the well and within extensions of the well
casing above the ground surface.
18
Use of a pitless adaptor allows the well to be
completed above ground surface. The well is then
easily accessible for maintenance or repairs, if
necessary, without excavating or disrupting the
earth. The adaptor is easily disconnected, and the
well pump and pump column can be removed from
the well. In Nova Scotia, such adaptors must meet
the standards of NSF (National Sanitation
Foundation).
The Water Storage (Pressure) Tank
In a domestic system for a single home where the
water supply meets the owner’s needs, a pressure
tank is usually the only point of artificial storage for
cold water. Newer tanks are commonly of the
bladder or diaphragm type. The pressure tank
serves the following functions:
• The tank allows you to draw some water from the
system when the pump is not running. Pressure
drops as water is used in the home. When the
pressure drops to a pre-set limit, the pump starts
and refills the pressure tank.
• The tank keeps the pump from running every
time water is used. The larger the tank, the more
water can be drawn without cycling (turning on
and off the pump). The more the pump cycles,
the faster it wears out.
• The storage tank provides water under pressure
to the distribution system. The most pressure it
can deliver is equal to the maximum pressure of
the pump.
When the yield of the well is limited, it may not be
possible to meet peak demands and some type of
additional storage must then be provided. The well
itself can provide some storage: 5.5 litres (1.2
gallons) per foot of water in a 152 mm (6 inch) well.
Appendix 2 gives storage volumes available in wells
of various diameters.
For larger water users (schools, hospitals,
campgrounds, municipalities, etc.), other storage
options may include an intermediate storage tank
with a second pressure pump, or an above-ground
storage tank with gravity feed.
The Distribution System
This system consists of the pipe, valves, and fittings
that conduct the water from the well to the various
points of use. The choice of pipe will depend on
underground soil corrosion, corrosion inside the
pipe, safe working pressure, effect of freezing, local
plumbing codes, ease of installation, and cost.
Plastic pipe is the most common material used in
household systems for submersible pumps and
distribution lines, and is available in various sizes
and strengths. Potable (drinking) water pipe must
meet the standards designated by AWWA
(American Water Works Association) or NSF
(National Sanitation Foundation).
The Treatment System
Once a water supply system has been hooked up
and is in normal use, a sample for water quality
should be taken for both bacterial and chemical
analysis. If the water does not meet established
guidelines or the owner’s aesthetic needs, a
treatment system or device can be installed. A port
or tap for sampling raw untreated water should
always be installed between the well and any
treatment device on any water system.
Fittings are usually available in the same sizes and
materials as piping, but valves are generally cast in
brass or other alloys. Where dissimilar metals are
present, corrosion may occur. Dissimilar metals
should not be in contact with one another. The use
of nonconductive plastic inserts between metal pipe
and fittings and/or the installation of sacrificial
anodes helps to minimize corrosion. The National
Plumbing Code of Canada now does not allow use
of galvanized steel fittings and pipe in water
distribution systems except under special
circumstances.
19
Water Quality
Why Should I Test?
Water for drinking, cooking, and other domestic
uses should be of good quality, that is, free from
organisms that may cause disease and from
chemical substances and radioactive matter that
may pose a health risk. The water should be
aesthetically appealing, which means that it should
be free from objectionable colour, odour, and taste.
Other considerations such as corrosiveness,
encrustation or excessive soap consumption due
to hardness are also important in terms of public
acceptance.
You, the homeowner, should have your water tested
to determine its quality. Harmful bacteria or
chemicals can be present in drinking water that
tastes, looks, and smells acceptable. Some of the
potential threats to groundwater quality in Nova
Scotia include petroleum products, sea water
intrusion, deicing salt, sewage disposal systems,
animal wastes, landfills, and pesticides.
A complete bacterial and chemical water quality
analysis allows the following:
✓ an assessment of any possible contaminants,
such as bacteria and ammonia from sewage,
chlorides from sea water intrusion, and arsenic
and uranium from natural minerals
✓ an assessment of potential aesthetic problems,
such as hardness or staining
✓ a comparison of all parameters tested to the
Guidelines for Canadian Drinking Water Quality
✓ validation of the accuracy of the analysis
What is Bacterial Quality?
Bacterial quality is usually assessed by a coliform
test. Coliform are a group of bacteria found in soil
and in large numbers in the intestines of warmblooded animals, including humans. Experience has
established the significance of coliform group
density as a measure of the degree of pollution and
of sanitary quality.
Before you use your well water, you should collect a
sample for bacterial analysis. Make sure the results
are acceptable
before drinking it.
If necessary, use
bottled water until
you receive the
results. After two
to four weeks of
regular household
use, recheck the
bacterial quality. Remember, disinfecting an
improperly located or constructed well will not
ensure its safety!
The only way you can
be sure your water
supply is safe is to
have it tested.
How Do I Test for Bacteria?
✓ Container
• Use a sterilized sample bottle with added sodium
thiosulfate preservative (a chlorine neutralizer).
Bottles are available from your local Department
of Environment and Labour office, water quality
laboratories, and from some hospitals. A list of
approved laboratories is available on the web at:
http://www.gov.ns.ca/enla/water/labs.htm
• Keep sample containers clean and free from
contamination before and after collecting the
sample. Do NOT open them prior to collecting the
sample.
• Examine the sample bottle for cracks, a missing
seal, or other signs that its sterility may be
compromised. If any of these indications are
found, discard the bottle and use a suitable one.
• Label the bottle with your name, location of your
water source, date, and time.
✓ Flush the System
• Do NOT take samples from a flexible hose or
garden hose or outside hose bib. Sample from
the cold water faucets only.
• For locations at which the sample must be
20
collected from a tap, inspect the outside of the
faucet. If water leaks around the outside of the
faucet, select a different sampling site.
• Remove any aerators, strainers, hose
attachments, mixing type faucets, purification
devices, or any other attachments, from the tap.
• If necessary, remove debris and sterilize the
faucet outlet, for example by swabbing with a
disinfecting wipe.
• If the sample is to be taken from a tap or a pump,
allow the water to run at least 5 minutes before
collection. This will help to remove stagnant water
from the distribution system.
✓ Collect the Sample
• If you have a chlorine disinfection treatment unit,
measure and record chlorine residual. Normally
free chlorine residual is measured, however total
chlorine residuals may be required on occasion.
In either case, mark “F” or “T” on the lab
requisition form, indicating free or total chlorine
residual. The majority of wells for private homes
do not have chlorine treatment units.
• Before taking the sample, reduce the tap flow
rate to approximately the width of a pencil. The
flow rate should be low enough to ensure that no
splashing occurs as the container is filled. Do not
adjust the flow rate while taking the sample. At
sampling points where the water runs
continuously, do not adjust the flow rate. Collect
the sample directly into the sterile bottle; do not
use a dipper or pail.
• While holding the sample container at the base,
remove the seal around the cap before
attempting to open the bottle.
• Remove the cap with the free hand. Be careful
NOT TO TOUCH the edge or bottom or inside of
the cap, or the neck or top or lip of the bottle.
Continue to hold the cap in one hand with the
inside facing down while the bottle is being filled.
Do NOT touch the interior of the cap or lay it
down. DO NOT breathe on the bottle or cap.
• Do NOT rinse the bottle.
• Fill the bottle to the fill line (usually about 3/4 full).
Do NOT allow the bottle to overflow. Space is
needed for the lab to add and mix test chemicals.
Carefully replace the cap.
• If the sample is to be taken from a well or spring
without a pump, tie a wire or string around the
neck of the bottle and lower it beneath the
surface if you cannot reach the water level. It is
very difficult to obtain a sample this way without
contaminating it during collection. If you can
reach the water, use a sterile glove on the hand
holding the bottle and collect the sample with the
bottle neck facing away from you into the flow.
Inexperienced samplers are likely to contaminate
the sample during collection.
• Complete all required parts of the laboratory
requisition form.
✓ Storage and Transport
• Refrigerate the sample immediately or place it in
a cooler with ice packs to maintain a water
temperature of about 4°C until delivered to the
lab. Samples should not be frozen.
• Transport the sample to an approved water
quality laboratory as soon as possible, and
definitely within 24 hours of collection. Check
ahead with the lab about days/time deadlines for
sample acceptance to ensure meeting the 24hour criterion.
What Do The Results Mean?
For potable waters submitted by private individuals,
the lab reports presence or absence of total coliform
bacteria and E. coli. Total coliform occur naturally in
soil and in the intestines of humans and animals.
E. coli are found only in the intestines of humans
and animals.
The maximum acceptable concentration (MAC) for
the bacteriological quality of private drinking water
systems for human consumption is NO (zero)
coliforms and NO (zero) E. coli detectable per 100 mL.
• NO sample should contain E. coli. The presence
of E. coli indicates that the source or the system
has been impacted by recent faecal
contamination and therefore the water is unsafe
to drink. If E. coli is detected, the water should be
retested immediately to confirm the result. While
waiting for the results, you should boil the
drinking water or use an alternative safe source.
• NO sample should contain other coliform
bacteria. The presence of other coliform bacteria
in non-disinfected well water in the absence of
E. coli means either that:
• the well is prone to surface water infiltration
and therefore at risk of faecal contamination, or
• a biofilm has developed within the well or
plumbing system.
21
In water systems that include disinfection, the
presence of total coliform bacteria indicates a
failure in the disinfection process or the presence
of a biofilm.
If a sample contains other coliform bacteria, the
drinking water should be retested immediately for
total coliform and E. coli.
The resampling described above is to confirm the
results (in case the sample was contaminated
during collection). While waiting for the results of the
second sample, either boil the water (rolling boil for
at least 1 minute) or use another alternative such as
bottled water, for any activity involving human
consumption. Examples of such activities include
drinking, cooking, washing foods such as fruits and
vegetables, dental hygiene such as brushing/rinsing
teeth, and preparation of infant formulas, juices and
ice cubes.
There are two possible results of the second test:
1. The second test result does not contain
coliform bacteria and E. coli (both are absent)
If the second test result indicates that coliform
bacteria and E. coli are absent, collect a third
sample for verification during the next 2 to 4 weeks.
• If the third sample result is ‘absent’ for both, the
water should be safe to drink. However, the water
should be resampled again after about 3 to 4
months to ensure that the contamination has not
recurred. Continue to monitor regularly, about
twice a year.
• If the third sample contains E. coli or other
coliform bacteria (either are ‘present’), follow the
directions in number 2 below.
2. The second test result contains coliform
bacteria and/or E. coli (one or both are present)
If the second test result still has coliform bacteria
and/or E. coli present, boil the drinking water or use
an alternative safe source and take the following
corrective actions:
• Conduct a sanitary survey to verify the safe
condition of the well, wellhead, pump, plumbing,
and surrounding area. Correct any identified
faults before proceeding to the next step. You may
want to obtain the services of a certified
professional.
22
If all the physical conditions are acceptable, then:
• Shock chlorinate the well and plumbing system
(see Appendix 1 for procedure).
• After disinfection, flush the system thoroughly
and take another sample (third sample) to
confirm that the water is safe to drink. This
sample can be taken after 48 hours IF testing
indicates absence of a chlorine residual. In the
absence of chlorine testing, wait about 5 days
after disinfection before sampling for bacteria. In
the meantime, continue to either boil the water
(rolling boil for at least 1 minute), or use an
alternative safe source such as bottled or
municipal water, for any water for drinking or
other human consumption.
If the third test result does not contain coliform
bacteria and/or E. coli (both are absent), an
additional (fourth) test should be taken after about 3
to 4 months to confirm that disinfection has been
effective and contamination has not recurred. If the
test has ‘absent’ results, continue to monitor
bacterial quality at least twice a year.
If the third test result still has either coliform bacteria
and/or E. coli present, an investigation should be
carried out by a certified professional to determine
the cause. Depending on the cause, some options
may be well reconstruction, well replacement, or
water treatment. In the meantime, continue to use
boiled water or an alternative source for human
consumption activities.
Note that a single sample with no bacteria does not
necessarily mean a safe water supply. To check the
safety of your water over the long term, continue to
monitor bacterial quality at least twice a year, or
more often if you suspect any changes in your water
quality. Sampling should be carried out when the
risk of contamination is greatest, such as during
spring thaw, during extended periods of heavy rain
or drought, or after lengthy periods of non-use.
What is Chemical Quality?
Chemical quality refers to all the dissolved mineral
matter in the water. It reflects the type of material in
the ground and how long the water has been in
contact with the material.
The following parameters are recommended for a
complete chemical analysis:
• Basic Chemical Parameters: sodium,
potassium, calcium, magnesium, hardness,
alkalinity, sulfate, chloride, silica, orthophosphate, nitrate plus nitrite-nitrogen,
ammonia-nitrogen, iron, manganese, copper,
zinc, color, turbidity, specific conductance, pH,
dissolved organic carbon.
• Additional Recommended Parameters:
arsenic, uranium, lead, fluoride.
• Specialized Parameters: many additional tests
are available. Such tests may require special
containers and sampling procedures. If you have
a specific concern,
you should
discuss it first with
Department of
Environment and
Labour, the
laboratory, or
a trained
professional.
Most mortgage and
lending institutions
will require analysis
for arsenic, uranium
and bacteria.
Most laboratories offer various package prices that
include most of the basic parameters and/or metals;
the packages may be cheaper than individual tests
and will usually provide more information.
How Do I Test for Chemical Quality?
✓ Container
• For most basic parameters, use a clean
polyethylene bottle available from your local
hospital or water quality laboratory or
Department of Environment and Labour office.
For additional or specialized parameters, discuss
the requirements with the laboratory or a trained
professional before sampling.
• Label the bottle with your name, address,
location of your water source, date, and time.
• Make sure all information on the requisition is
filled out completely.
✓ Flush the System
• If the sample is to be taken from a tap or pump,
run the cold water tap 10 minutes, if possible.
This will help to flush stagnant water that may
have artificially elevated metal concentrations
from the distribution system.
✓ Collect the Sample
• Rinse bottle and cap 2 to 3 times unless
specialized sampling uses containers with
preservatives and/or requires non-rinse
procedures.
• Turn flow volume down so that water runs gently.
The flow rate should be low enough to ensure that
splashing is minimized as the container is filled.
• Sample for sensitive parameters (organics,
metals) first. Filtration and preservation may be
necessary for metals, depending on the purpose
of sampling.
• Fill bottle to top (overflow), unless specialized
sampling uses containers with preservatives
added. Cap tightly with no air gap.
• Measure temperature of the flowing water if you
have a thermometer available.
✓ Storage and Transport
• Refrigerate the sample immediately or place it in
a cooler with ice packs to maintain a water
temperature of about 4°C until delivered to the
lab. Samples should not be frozen. Samples
should be kept in the dark.
• Transport the sample to an approved water
quality laboratory as soon as possible, preferably
within 24 hours of collection. If samples cannot
be delivered within that time, check with the lab
for sample holding times.
23
What Do The Results Mean?
The chemical quality of the water should be
compared to the latest Guidelines for Canadian
Drinking Water Quality. Guidelines for selected
common parameters are shown in Table 1. If any
parameter poses a health problem, or is present at
levels exceeding those expected for normal
uncontaminated groundwater, then an investigation
is necessary to determine the source of the
problem. Your local Department of Environment and
Labour office can help with this.
TABLE 1 Guidelines for Selected Chemical Parameters
Parameter (1)
Maximum Acceptable
Interim Maximum
Concentration,
Acceptable
mg/L (2)
Concentration, mg/L (3)
Arsenic (12)
0.025 (under review)
Chloride
Colour
Copper (5)
Fluoride (6)
1.5
Hardness (as CaCO3)
Iron
Lead (5)
0.010
Manganese
Nitrate-nitrogen (8)
10.0
pH (no unit)
Sodium (9)
Sulphate (10)
Sulphide (as H2S)
Temperature
Total dissolved solids
Turbidity (11)
1 NTU (under review)
Uranium
0.02
Zinc (5)
Aesthetic
Objective,
mg/L (4)
≤250
≤15 TCU
≤1.0
(7)
≤0.3
≤0.05
6.5-8.5
≤200
≤500
≤0.05
≤15°C
≤500
≤5 NTU
≤5.0
Notes:
The numbers in brackets in Table 1 refer to explanatory notes on page 25.
The information in Table 1 is taken from the Summary Table of Guidelines for Canadian Drinking Water Quality
(April 2003) on the Health Canada website http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/index_e.html. These
guidelines are updated frequently. Please check the Health Canada website for the most current information.
24
(1) Concentrations in mg/L unless otherwise noted.
TCU = true colour unit. NTU = nephelometric
turbidity unit.
(2) Maximum acceptable concentrations (MACs)
have been established for certain substances
that are known or suspected to cause adverse
effects on health. They have been derived to
safeguard health on the basis of lifelong
consumption. The use of drinking water for all
domestic purposes, including personal hygiene,
has been considered in the derivation of
guidelines. However, water of higher quality
may be required for special purposes, including
renal dialysis.
Drinking water that continually contains
substances at levels greater than the MAC will
contribute significantly to consumers’ exposure
to the substance and may, in some cases,
induce deleterious effects on health. Short term
exposure above the MAC does not necessarily
mean that the water constitutes an undue risk
to health. The amount, time, as well as the
toxicity of the substance must be considered.
(3) Interim maximum acceptable concentrations
(IMACs) are recommended for substances with
insufficient toxicological data to derive an MAC
with reasonable certainty. They consider
available health-related data but employ a
larger safety factor to account for uncertainties.
The IMACs are reviewed periodically as new
information becomes available.
(4) Aesthetic objectives (AOs) apply to certain
substances or characteristics of drinking water
which can affect its acceptance by consumers
or interfere with practices for supplying good
quality water. Where only AOs are specified, the
values are below those considered to constitute
a health hazard.
(5) At the point of consumption. Because firstdrawn water may contain higher concentrations
of metals than are found in running water after
flushing, faucets should be thoroughly flushed
before water is taken for consumption or
analysis.
(6) It is recommended that the concentration of
fluoride be adjusted to 0.8 - 1.0 mg/L, which is
the optimal range for the control of dental
caries.
(7) Public acceptance of hardness varies
considerably, thus no MAC has been
established. Generally, hardness levels between
80 and 100 mg/L (as calcium carbonate) are
considered acceptable. Levels greater than 200
mg/L are considered poor but can be tolerated.
Levels in excess of 500 mg/L are usually
considered unacceptable for most domestic
purposes. Where water is softened by sodium
ion exchange, it is recommended that a
separate, unsoftened supply be retained for
culinary and drinking purposes.
(8) Equivalent to 45 mg/L as nitrate. Where nitratenitrogen and nitrite-nitrogen are determined
separately, the level of nitrite-nitrogen should
not exceed 1.0 mg/L (3.2 mg/L as nitrite).
(9) It is recommended that sodium be included in
routine monitoring programs, as levels may be
of interest to authorities who wish to prescribe
sodium-restricted diets for their patients.
(10) There may be a laxative effect in some people
when sulphate levels exceed 500 mg/L.
(11) An average MAC is 1 NTU for water entering a
distribution system so disinfection is not
compromised. A less stringent value may be
permitted if it is demonstrated that the system
has a history of acceptable microbiological
quality and that a higher turbidity value will not
compromise disinfection. Please note that the
MAC for turbidity is under review. It will likely be
lowered in the near future for surface water and
groundwater under the direct influence of
surface water. An AO of 5 NTU is set for water
at the point of consumption.
(12) The guideline for arsenic is under review. It will
likely be lowered in the near future.
25
Water Treatment
The most common parameters
exceeding the aesthetic
guidelines in Nova Scotia are
hardness, iron, and manganese.
If the water is unacceptable to the
consumer, a treatment device
can be installed. The most
common health-related problems
Appropriate treatment
begins with a good
chemical analysis and
good background data. A
smart homeowner will take
the results to a reputable
treatment dealer.
are arsenic, nitrate and uranium,
depending on the location.
Treatment is available for most of
these problems. For example,
most households with an arsenic
problem treat one tap for drinking
and cooking purposes. Common
problems, causes and solutions
are summarized in Table 2.
TABLE 2 Common Water Quality Problems and Possible Solutions
PROBLEM
PROBABLE CAUSE
POSSIBLE SOLUTIONS
Health problems
Coliform bacteria
Investigate source first
Chlorination, Ultraviolet light Ozonation
Hard scaly deposits in kettles
Hardness
Water softener
and piping, bathtub ring, soap
scum, high soap consumption
Red or orange stains on laundry
Iron
Water softener, Greensand
or fixtures, metallic taste, rust
filter, Chlorination/filtration
particles after water sits
(depending on concentration)
Black stains on laundry or
Manganese
Water softener, Greensand filter
fixtures, metallic/bitter taste in
Chlorination/filtration (depending
coffee and tea
on concentration)
Red to brown slime in toilet tank,
Iron bacteria
Shock chlorination of water source
iron staining, unpleasant taste
and entire system
or odour
Chlorination/filtration
Acid water, causing corrosion of
Low alkalinity, presence
Soda ash
piping (green stains due to
of carbonic acid usually,
Neutralizing tank
copper corrosion)
sometimes mineral acids
such as sulfuric acid
Rotten egg odor and flavor,
Hydrogen sulfide and/
Greensand filter
silverware may turn black,
or sulfate-reducing
Chlorination/filtration
worse in hot water
bacteria
Aeration, Activated carbon
Cloudy, dirty or muddy
Turbidity
Fine filters (sand diatomaceous
appearance
earth), Coagulation (alum) & filtration
High blood pressure
Sodium
Reverse osmosis, Distillation (single tap)
Salty taste, corrosive
Chloride
Reverse osmosis, Distillation
(single tap), Anion exchange
Gas bubbles escaping from water
Gases such as methane
Aeration, Activated carbon
Laxative effects
Sulfate
Reverse osmosis, Distillation (single tap),
Anion exchange
Health problems
Arsenic
Reverse osmosis, Distillation, Activated
alumina, Ferric hydroxide, Anion exchange
Health problems
Uranium
Reverse osmosis, Distillation (single tap)
Oily smell or film on water
Gasoline and/or oil
Investigate and eliminate source first
Activated carbon, Gravity separation
‘Blue babies’ in formula-fed
Nitrate
Reverse osmosis, Anion exchange
infants under 6 months
Use nitrate-free water for infant formula
preparation
26
Well Maintenance
How Often Should I Check Water Quality?
You should be responsible for ongoing monitoring of
your well water quality. The bacterial quality should
be checked every six months. The chemical quality
should be checked every one to two years, or earlier
if you notice any change, such as increased
turbidity, staining, or hardness, or a change in taste
or odor. The parameters to be analyzed are the
same as those listed previously.
How Can I Protect my Water Supply for
the Future?
Protecting your water source and water supply
system must be your prime consideration. Protection
starts with proper location and construction of the
well, followed by disinfection. Chemical disinfection
or chlorination is
essential to ensure
that your well,
pump, and pipes
are free from
bacteria that can
be introduced
during well
construction, pump
installation, and
well or pump
repair. Disinfection
is the final step
after all defects in
location and
construction have
been corrected and before samples are collected for
bacterial examination. Any time that the pump or
lines are removed for any reason, or repair work is
carried out on the well, it must be disinfected.
Frequent testing
checks the integrity
of your well, lets you
know if corrective
measures are
required, and warns
you if another
activity is having an
impact on your well.
Disinfection will kill only the bacteria present in the
well or system. If there is some external source of
contamination, the problem will be solved only
temporarily by a single application of chlorine
solution. Improperly located and constructed water
supplies are never safe, and disinfection cannot be
relied on for 100 % destruction of harmful bacteria.
The most commonly used methods of disinfection
involve chlorine either in liquid or tablet formulations.
Appendix 1 contains suggested procedures.
The final protective measures are taken when the
pump and other components of the distribution
system are installed and the system is made
operational. The purpose is to protect against
surface water entering directly into the top of the
well or the annular space.
You should check at least once a year that:
• the cap is securely in place and undamaged
• the vent screen in the cap is intact and not
blocked by vegetation growth
• connections in the well casing are properly
sealed
• drilled well casing has no holes or cracks and
there are no gaps between the casing and the
ground around it
• joints and connections in dug well crocks are not
leaking, and vents are shielded and screened
• surface drainage near the well is directed away
from the well casing or crocks
• surface water does not pond near the well
• the well pump and distribution system is
functioning properly, with no leaks
Changes in the quantity and quality of the water
should be investigated immediately.
You can also follow some of these simple rules:
• Do not allow liquids or wastes from contaminant
sources such as garbage and manure piles to
drain towards the well.
• Grow a grass buffer and do not treat the area
around the well with pesticides or fertilizer.
• Do not use bark mulch or wood chips near a dug
well.
• Do not bury brush piles, stumps or other such
debris on your property, especially near to or
upgradient of a dug well.
• Do not flush oils, detergents, paints, solvents or
other chemicals down the toilet.
• Do not dispose of waste oil, paints, pesticides,
etc. on the ground.
• Do not allow animals to urinate or defecate near
the well.
If you follow these guidelines, your well should
provide good quality water for a long time.
27
Summary
S
Here are some Dos and Don’ts to keep in mind.
DO construct a well before you build.
DO hire a certified water well contractor and inquire
about his reputation and qualifications.
DO require a written contract, but don’t try to be a
superintendent over the contractor. He knows his job
and his judgement can be trusted.
DO hire a certified pump installer and ensure that a
pitless adaptor is used in new installations.
DO check bacterial and chemical quality regularly.
28
DON’T take an individual’s word that an ample
supply of water will be available from a well without
obtaining existing information from your local
Department of Environment and Labour Office and
a reputable well contractor.
DON’T compare contractors’ abilities and proposals
merely on the per metre (per foot) prices they
charge. A cheap well may mean poor materials and
workmanship and may prove more costly at a later
date.
DON’T locate a well too close to sources of
contamination. Check regulatory distances with your
local Department of Environment and Labour Office.
References
Driscoll, F.G. 1986.
Groundwater and wells, 2nd edition.
Johnson Division, St. Paul, Minn.
Health Canada.
Guidelines for Canadian Drinking Water
Quality. Latest edition of summary table
on Health Canada’s website:
http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/index_e.html
Health and Welfare Canada.
Guidelines for Canadian drinking water quality,
supporting documentation (ongoing updates).
Health and Welfare Canada. 1993.
Water treatment principles and applications.
Shawinigan Engineering Maritimes Ltd. 1980.
Groundwater protection guidelines in Nova
Scotia.
Report to N.S. Department of Environment and
Labour.
U.S.E.P.A. 1991.
Manual of individual and non-public water
supply systems.
EPA 570/9-91-004.
U.S.E.P.A. 1991.
Manual of small public water supply systems.
EPA 570/9-91-003.
Water Systems Council. 1993.
Water systems handbook, 10th edition.
Water Systems Council, Chicago, Ill.
29
Appendix 1
Disinfection of Water Wells by
Chlorination
Chlorination, or "shock chlorination", is the process
of flushing your well and water system with a
chlorine solution to kill bacteria and other
microorganisms. Disinfection by chlorination is
usually recommended if a water sample from the
well has tested positive for bacteria. It is an effective
method to eliminate a "one-time" case of bacterial
contamination; however, if there is an on-going
problem related to faulty well construction or
contaminated groundwater, disinfection is only a
temporary fix and the problem should be
investigated and corrected at the source.
How do I Disinfect my Well?
It may take up to 24 hours to complete the
disinfection process. Before you begin, make sure
you store enough water to meet your household
needs during this period. If you have a water
softener or other treatment units, check with your
treatment dealer whether disinfection could
adversely affect the unit or not.
Step 1. Mix the amount of liquid bleach shown in
Table 1-1 for your well in 10 to 20 litres (2 to 5
gallons) of water. Use common, unscented
household bleach that does not contain detergent or
other additives such as fabric-guard. Chlorine can
be dangerous if not used properly. Always follow the
directions on the label for safe storage, handling and
use.
Step 2. Remove the well cap and pour the mixed
chlorine solution into the well. If the well is buried
with the old type of well seal top, either expose the
top of the well, remove the well seal and pour the
solution directly into the well, or pour the solution
through a clean funnel into the air vent or siphon
through the vent (flush the air line with clean water
after chlorination).
30
Step 3. Open one faucet in the system and let the
water run until the chlorine odour is detected. Turn
this faucet off. Repeat at each faucet in the system
in turn, one at a time, until all faucets have been
completed (include inside and outside faucets, cold
and hot water, dishwashers, toilets, baths, showers,
sinks, etc.).
Step 4. If possible, connect a garden hose to a
nearby tap and place the other end in the well. Turn
on the tap and allow the water to circulate for about
one hour to ensure that the chlorine is thoroughly
mixed in the well. During this process, add
additional chlorine solution if the chlorine odour is
not strong. Note that although recirculation is
desirable if possible, it may not be appropriate in
wells with screens, gravel packs, heavy iron buildup,
soft or caving zones, and other less common
conditions. If you have any concerns, contact your
local Department of Environment and Labour Office
or a certified contractor for information.
Step 5. Seal the top of the well and let the system
sit idle for about 12 hours, preferably overnight. Do
not leave chlorine for more than 24 hours as it may
affect some pump parts.
Step 6. After this time, flush the system by
discharging the chlorinated water through an
outside tap until the chlorine odour has completely
disappeared. Pump at a low rate, in the order of 10
litres per minute (2 gallons per minute) or less. This
procedure may take several hours, or longer. IF you
have a low yield well, you may have to allow the
well to recover between pumping periods. During
the flushing process, do not discharge the
chlorinated water to a natural water body (such as
streams or lakes, etc.) or to areas where it can
harm desired vegetation (e.g., vegetable gardens,
landscaped areas, etc.). Do not discharge this water
into the on-site sewage disposal system.
TABLE 1-1
Depth of
water in
well
metres feet
1
3
5
10
30
50
100
3
10
15
30
100
150
300
Amount of unscented household
bleach1
Drilled Well
Dug Well
Casing diameter Casing diameter
15 cm (6 inches)2 92 cm (36 inches)2
40 mL
1.5 L
120 mL
4.5 L
200 mL
7.5 L
400 mL
15.0 L
1.2 L
2.0 L
4.0 L
Notes:
1 Assumes liquid bleach with approximately
5.2% hypochlorite. This will produce about 100
mg/L of chlorine solution when mixed with the
water in the well.
2 For wells with other casing diameters, contact
your local Department of Environment and
Labour Office
over the long term, continue to monitor bacterial
quality at least twice a year, or more often if you
suspect any changes in your water quality.
IF the sample result indicates either coliform
bacteria and/or E. coli are present, it is
recommended that the well owner seek advice from
Department of Environment and Labour or a
certified professional. In the meantime, continue to
use boiled water or an alternative source for human
consumption activities.
Final Notes
You may experience some temporary
inconveniences as a result of the disinfection
process such as dirty or discoloured water, staining,
or sedimentation problems. However, the water
should clear with time. In some cases, a few days
may be necessary. Do not use the water for
aquariums or pets during this time. Check with your
physician about other uses of the water, such as
bathing, if you have allergies or other medical
concerns.
Example Calculation for a Drilled Well:
Measurements:
• Well diameter = 150 mm (6 in)
• Well depth = 60 m (200 ft)
• Depth to water from surface = 10 m (30 ft)
Calculations:
• Depth of water in well = 60 - 10 = 50 m or
depth of water in well = 200 - 30 = 170 ft
• From Table 1-1, required volume of bleach to
get 100 mg/L solution is about 2 litres
Please note that under some conditions, such as
biofilm buildup in a well, more than one disinfection
may be required.
If you have any questions about disinfecting your
well, or wish to have a certified person do the work
for you, please contact your local Department of the
Environment and Labour Office for information, or
check the certified contractor list at:
www.gov.ns.ca/enla/water
Sampling after Disinfection
After disinfection, sample the water for total coliform
and E. coli bacteria to confirm that the water is safe
to drink. Wait about 5 days after disinfection before
sampling. While waiting for the results, any water for
human consumption should be boiled (rolling boil)
for at least 1 minute, or use an alternative source.
IF the sample result indicates that both coliform
bacteria and E. coli are absent, confirm that
disinfection has been effective by 2 additional
samples, one in the next 2 to 4 weeks, another after
3 to 4 months. To check the safety of your water
31
Appendix 2
Volume of Water in Wells
It is often good to know how much water is actually
stored in your well. Depending on well depth and
pump setting, a low-yield drilled well with a high
static water level may have a day’s supply of water
in storage in the well itself. During dry seasons of
the year, many dug well owners check regularly to
see how much water is in their well, and increase or
decrease their use accordingly. You can calculate
your well volume easily by using Tables 2-1 and 2-2.
TABLE 2-1
Well Diameter
(Drilled Wells)
MM
Inches
100
4
130
5
150
6
200
8
Well Volume
(amount of Water in Well)
Litres/M
Gallons/ft
8.1
0.54
12.7
0.85
18.2
1.22
32.4
2.17
Example Calculation, Drilled Well:
Measurements:
• Well diameter 150 mm (6 in)
• Well depth 60 m (200 ft)
• Depth to water from surface 15 m (50 ft)
• Pump intake setting 58 m (190 ft) from surface
Calculations:
• Depth of available water in well = 58-15 = 43 m or
• Depth of available water in well = 190-50 = 140 ft
• Volume of water stored in well = 43 (depth of
water from line above) x 18.2 (for 150 mm well
from Table 2-1) = approx. 780 litres or
• Volume of water stored in well = 140 (depth of
water from line above) x 1.22 (for 6 inch well from
Table 2-1) = approx. 170 gallons
32
TABLE 2-2
Well Diameter
(Dug Wells)
MM
Inches
760
30
915
36
1070 42
1220 48
Well Volume
(amount of Water in Well)
Litres/M
Gallons/ft
456
30.6
657
44.0
894
60.0
1168
78.3
Example Calculation, Dug Well:
Measurements:
• Well diameter 915 mm (36 in)
• Well depth 6 m (19.7 ft)
• Depth to water from surface 1.0 m (3.3 ft)
• Pump intake setting 5.8 m (19.0 ft) from surface
Calculations:
• Depth of available water in well = 5.8-1 = 4.8 m or
• Depth of available water in well = 19-3.3 = 15.7 ft
• Volume of water stored in well = 4.8 (depth of
water from line above) x 657 (for 915 mm well
from Table 2-2) = approx. 3150 litres or
• Volume of water stored in well = 15.7 (depth of
water from line above) x 44 (for 36 inch well from
Table 2-2) = approx. 690 gallons
Nova Scotia Environment and Labour Regional Offices
REGION
STREET AND MAILING ADDRESS
TELEPHONE NO.
FAX NO.
Central Region
Bedford
1595 Bedford Highway
Suite 224, Sunnyside Mall
Bedford, NS B4A 3Y4
(902) 424-7773
(902) 424-0597
Sheet Harbour
Fire Hall, 22835 Highway #7
PO Box 35
Sheet Harbour, NS B0J 3B0
(902) 885-2462
(902) 885-2743
Northern Region
Truro
44 Inglis Place, 2nd Floor, Suite 3
PO Box 824
Truro, NS B2N 5G6
(902) 893-5880
(902) 893-0282
Pictou
Middle River Pumping Station, Granton Road
PO Box 675
New Glasgow, NS B2H 5E7
(902) 396-4194
(902) 396-4765
Amherst
32 Church Street,
2nd Floor
Amherst, NS B4H 3A8
(902) 667-6205
(902) 667-6214
Antigonish
Kirk Place, 219 Main Street, Suite 205
Antigonish
NS B2G 2C1
(902) 863-7389
(902) 863-7411
Western Region
Kentville
136 Exhibition Street
Kentville
NS B4N 4E5
(902) 679-6088
(902) 679-6186
Middleton
101 Magee Drive
PO Box 1000
Middleton, NS B0S 1P0
(902) 825-2123
(902) 825-4471
Bridgewater
60 Logan Road
Bridgewater
NS B4V 3J8
(902) 543-4685
(902) 527-5480
Yarmouth
13 First Street
Yarmouth
NS B5A 1S9
(902) 742-8985
(902) 742-7796
Eastern Region
Sydney
295 Charlotte Street
PO Box 714
Sydney, NS B1P 6H7
(902) 563-2100
(902) 563-2387
Port Hawkesbury
400 Reeves Street
Unit 126
Port Hawkesbury, NS B9A 2R5
(902) 625-0791
(902) 625-3722
Head Office
Halifax
5151 Terminal Road
PO Box 697
Halifax, NS B3J 2T8
(902) 424-5300
(902) 424-0501
33
Notes or Sketches
34
Sample Well Drilling Contract
BETWEEN
_________________________________________________________________________________________________
Name of Drilling Company (hereinafter called the ‘Contractor’)
License Number
_________________________________________________________________________________________________
Address/Phone/Fax of Drilling Company
AND
_________________________________________________________________________________________________
Person or Firm Contracting this Order (hereinafter called the ‘Customer’)
_________________________________________________________________________________________________
Address/Phone/Fax of Customer
The Customer agrees to retain the services of the Contractor for the purposes of constructing a well or wells at the
following location:
_________________________________________________________________________________________________
The Customer warrants that the premises belong to or are under his/her legal control, and that he/she has full right and
authority to enter into this drilling contract.
The Customer shall be responsible for access to the drill site(s). The location(s) of the well(s) shall be agreed upon by the
Contractor and the Customer.
The Customer shall permit the Contractor and his/her representatives free and unobstructed access to the site of the water
well(s) for the purpose of carrying out this agreement.
The Contractor warrants that he/she has liability insurance of $ _______________________________________________
The approximate starting date for construction of the well(s) is: _______________________________________________.
If the Contractor has not started to construct the well(s) after 10 days of the approximate starting date, the Customer has
the option to terminate this contract by verbal or written notice, and the Contractor will return the Customer’s deposit.
The Contractor shall ensure that the water well(s) is (are) constructed, cased, tested and completed in compliance with the
Well Construction Regulations made under Section 110 of the Environment Act of the Province of Nova Scotia.
The well(s) shall be drilled to a sufficient depth to meet expected needs (or minimum requirements if applicable). Should
insufficient quantity be obtained by 91 metres (300 feet) depth, the Customer or his/her agent will be notified so that
options may be evaluated. Drilling will be discontinued at any time upon direction from the Customer.
The Contractor warrants and guarantees that the work to be performed under this Agreement shall be executed and
completed in a proper and workmanlike manner, but does not warrant or guarantee that water will be obtained nor the
quantity or quality of any water which may be obtained.
The Customer agrees to pay the Contractor for the work at the following rates:
Drilling
$__________________
per metre (per foot) of depth from the surface
Casing
$__________________
per metre (per foot) (materials and installation)
One drive shoe
$__________________
materials and installation
One well cap
$__________________
materials and installation
35
Extra costs
Geological conditions are reasonably well known in most areas, but unexpected conditions may occur.
Such conditions may necessitate the use of additional materials or work (such as drilling mud or foam,
liner casing, well screens, cement, pumps, tanks, pipes, etc.). These may be employed if deemed
necessary by the Contractor and charged to the Customer accordingly. The Contractor will contact the
Customer to inform him/her of such conditions and possible extra costs prior to conducting the work.
Additional materials such as the above, if not required by geological conditions but recommended by
N.S. Department of Environment and Labour, or requested by the Customer, will be supplied at the
Contractor’s current retail prices.
Extra labour
Any additional pumping or developing required for bacteriological or chemical testing above and beyond
regulatory requirements, or use of the Contractor’s equipment and personnel for any service not referred
to above will be an additional cost.
Taxes
All work and materials are subject to applicable taxes in addition to the above, payable by the Customer.
Payments
The Customer agrees to pay the Contractor as follows:
(a) $____________ deposit on signing of this contract towards moving and setup costs, which shall be
credited towards the total cost.
(b) the balance in a lump sum as described below.
All accounts rendered by the Contractor to the Customer, whether interim, final or otherwise, shall be
paid within 30 days of the date set out on the accounts. Accounts not paid within the 30 day period
shall accrue interest at the rate of ______% per month calculated from the date set out on the accounts.
The Contractor guarantees workmanship and materials to be free of defect for a period of ___________ years from the
equipment leaving the well drilling premises. Workmanship and materials on a pump system purchased from and installed
by the Contractor are guaranteed to be free of defect for a period of ___________ years from the date of installation.
These guarantees shall be void if explosives, dry ice, hydro-fracturing, etc. are used by anyone (including the Contractor)
in the well(s).
Upon completion of the work, the Contractor shall complete a well construction report(s) as required by N.S. Department
of Environment and Labour, and provide copies to the Department, the Customer, and shall keep a copy for a period of at
least 2 years from the date of completion of the well(s).
This agreement is subject to other terms and conditions between the Contractor and the Customer as set out immediately
below:
__________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
I ACCEPT THE ABOVE AGREEMENT, DATED THIS ______________ DAY OF ______________________ 20_________
AT ______________________________ IN _________________ COUNTY, PROVINCE OF _______________________
__________________________________________________________________________________________________
CUSTOMER
36
CONTRACTOR/AUTHORIZED AGENT
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