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Buying a House with a Well and Septic SystemIn rural areas,
many homes do not have connections to municipal water and sewer lines.
Homeowners rely upon privately owned or communal (shared) wells as their
drinking water source, and individual septic systems to treat and discharge
their wastewater. Homeowners must ensure that their well water is safe to drink,
and that their well and septic system are properly maintained. A malfunctioning
well or septic system can pose a health risk to your family and neighbours, and
can be expensive to repair or replace. It is therefore important to conduct a
detailed inspection of both the well and septic system prior to purchasing a
home. This document will describe how wells and septic systems function and how
to inspect them. WellsWhen you are
purchasing a home with a private water supply (a well), there are three key
items to consider:
Well Systems There are three
common types of wells: dug, bored and drilled. Dug
and bored wells (60-120 cm/24- 48 in. diameter) are commonly used to
produce water from shallow surface aquifers (less than 15 m/50 ft. deep); and,
they are prone to contamination from surface water infiltration and to water
shortages (see Figure 1). An aquifer is an underground formation of
permeable rock or loose material, which can produce useful quantities of water
when tapped by a well. Another type of well used in surface aquifers is a sand
point well (2.5-5 cm/1-2 in. diameter), which is a pointed well screen connected
to a small diameter pipe driven into water-bearing sand or gravel.
Drilled wells
(10-20 cm/4-8 in. diameter) are commonly used to penetrate deeper aquifers (15
to greater than 60 m/50 to greater than 200 ft. deep), are more costly to
construct, but generally provide a safer source of drinking water (see Figure
2).
Common features
of well systems include: casing
– structure around the well hole, which keeps it from collapsing. It could be
a steel casing, concrete rings or an open hole in bedrock. inlet
– allows water to enter the well from the bottom. There might be a screen at
the inlet to prevent fine particles from entering the well and a foot-valve
(check valve) to maintain system prime and pressure. pumping
system
– includes pump, piping and necessary electrical connections to pump water
from the well into the house, and a pressure tank to maintain constant water
pressure in the house. Submersible pumps are usually used in drilled wells,
while shallow wells usually use centrifugal pumps, which are located out of the
well, most likely in the basement or in a pump house. surface
protection – prevents surface water and contaminants from entering the
well. Includes: watertight seal placed around the casing (annular seal), well
cap 0.3–0.4 m (12-16 in.) above the ground, and mounded earth around the top
of the well casing to divert rainwater. Well
Inspection Checklist The well should
be inspected before the house is purchased. If there is a problem with the
physical state of the well (for example, cracked seals, settled casing) contact
a licensed well contractor to correct the problem. Check the Yellow Pages™
under “water well drilling and service” to find a local licensed well
contractor.
Water
Quantity Wells draw water
from aquifers, which are zones of saturated permeable soil or rock. Some types
of soil make for good aquifers, such as gravel and fractured bedrock that can
support high water pumping rates, while other types of soil make for poor
aquifers, such as silty sand and clay that cannot support high water pumping
rates. Wells can run
dry for the following reasons:
If there is a
water supply problem, a licensed well contractor should be consulted. Solutions
may include: water conservation in the home, digging a deeper well, unplugging a
fouled well screen or replacing a corroded well casing or screen. The cost of
fixing the problem should be considered when negotiating the sale price for the
home. There are three
sources of information to help determine if a well can produce a sufficient
quantity of water:
Local
Knowledge: The best indication of whether there is sufficient water supply is
to ask the owner, neighbours or local well drillers if there have been any
problems with wells running dry on the property and in the area. Generally,
shallow wells are more likely to have problems with water shortages than deep
wells, as shallow wells draw water from surface aquifers, which can fluctuate
greatly depending upon the amount of precipitation. Well Record:
Obtain a copy of the well record from the previous owner or the Ministry of the
Environment. The pumping water level indicates if the well is shallow or deep
(less than 15 m/50 ft. is considered a shallow well). The recommended pumping
rate should be greater than 14 L/min (3.6 US gal/min). Water
Recovery Test: A licensed contractor can be hired to conduct a recovery test
which involves pumping water out of a well and then giving it time to recharge.
This can help you determine how much water you can draw from the well. A well
should be able to pump 14 L/min (3.6 US gal/min) for 120 minutes or 450
L/person/day (119 US gal/person/day) (Source: MOE, Procedure D-5-5, 1996). A
recovery test can cost $200-$300 (Source: Gilles Bourgeois Well Drilling Ltd.,
St. Albert, ON, 2003). Water
Quantity Checklist
Water Quality The quality of
the well water is very important. Poor water quality can lead to health
problems, unpleasant taste and odour, and costly treatment systems and/or the
costly use of bottled water. Well water can be contaminated with bacteria and
chemicals. Common sources of contamination include infiltration from septic
systems, manure runoff, pet waste, or road chemicals as well as dissolved
chemicals naturally present in the groundwater such as calcium, sulphur,
chloride or iron. Water
Sampling Your offer of
purchase should always include a requirement that closing is conditional upon an
acceptable water quality evaluation. It would be ideal to take three water
samples, about a week apart, with one of the samples taken after a rainstorm
when surface water contamination is most likely. If possible, take the water
samples yourself. The three samples should be analyzed for: total coliform, E.
coli, and nitrate ($30 each time) while one of the samples should also be
analyzed for: sodium, hardness, sulphate, chloride, lead, iron, manganese and pH
($80). Ask the laboratory to indicate the drinking water standards along
with the results. Additional analyses can be conducted including: metals scan
($70), pesticides if the well is in an agricultural area with heavy pesticide
use ($250), or gasoline and solvents if the well is near a gas station or
industrial area ($70). Contact your
local public health office for instructions on where to obtain appropriate
sterile sampling bottles and where to submit water samples for testing. Bacteria
and nitrate are analyzed free of charge in some provinces through local public
health or Ministry of Environment offices, while the additional parameters will
have to be analyzed at a private analytical laboratory. If possible,
samples should be taken from a tap between the well pump and any water treatment
units and/or pressure tank. Follow the directions on the sample submission form
for proper water sampling procedures. Test Results
– What They Mean If
concentrations are higher than the limits described below, consult a water
treatment systems supplier to determine if a water treatment technology is
appropriate. It is preferable to get several quotations. Health
Indicators Escherichia
coli (E. coli) or faecal coliform: These bacteria are found only in the digestive
systems of humans and animals. Their presence in your well water is usually the
result of contamination by manure or human sewage from a nearby source such as a
septic system or agricultural fields. Drinking water contaminated with E. coli
or faecal coliform causes stomach cramps and/or diarrhoea as well as other
problems and can even cause death. The drinking water standard for both E. coli
and faecal coliform is 0 counts/100 ml. A value of 1 or more indicates
that the water is unsafe to drink. Total
coliform:
This group of bacteria is always present in manure and sewage, but is also found
naturally in soil and on vegetation. The presence of these bacteria in your well
water may indicate that surface water is getting into your well. A total
coliform value of 1-5 suggests that the safety of the water is doubtful, while a
value of greater than 5 indicates that the water is unsafe to drink. Nitrate:
The presence of nitrate in your well water is usually the result of residential
yard or agricultural fertilizers, or seepage from septic systems. Infants less
than six months old can become sick from drinking formula made with water high
in nitrate (greater than 10 mg/L). If you have an infant less than six months
old, it is recommended to use bottled water. Sodium/Potassium
Chloride:
Individuals who are on a sodium- (salt) reduced diet should consult with their
physician if the level of sodium in their well water exceeds 20 mg/L. Domestic
water softeners typically use sodium chloride and this increases the level of
sodium in the drinking water. Potassium chloride is an alternative to sodium
chloride for softening water. However, individuals suffering from hypertension,
kidney disease or congestive heart failure should consult their physician prior
to using drinking water containing high levels of sodium or potassium. A
separate, unsoftened water supply (by-passing the water softener) can be
installed for drinking and cooking purposes if sodium or potassium is a health
concern. Sulphate:
At concentrations above 500 mg/L, sulphate can have a laxative effect and give a
bitter taste to the water. Lead:
Lead concentrations in water are likely due to lead piping. Concentrations as
low as 0.01 mg/L could cause longterm health problems. Aesthetic
indicators Hardness:
Hardness is a measure of calcium and magnesium in water. These elements
precipitate with carbonate in boilers and pots to form scale. Hardness also
makes it difficult to form lather, requires more soap, and creates a soap scum.
Many homeowners decide to purchase a water softener, which replaces
calcium and magnesium ions with sodium or potassium ions. Hardness (as calcium
carbonate) above 80 mg/L could require a water softener. Chloride:
Chloride concentrations above 250 mg/L can give a salty taste to the water and
may corrode piping. Iron and
Manganese: Well water with iron concentrations above 0.3 mg/ L and manganese
concentrations above 0.05 mg/L could stain plumbing fixtures and clothing; water
may appear rust coloured or have black specks in it; can also cause a foul taste
in the water and bacterial fouling of the well screen. pH:
pH values of less than 6.5 or greater than 8.5 may cause corrosion of piping. Drilling a
New Well The cost of a
new well depends on the depth of the well and the local market. The following
table provides an example of typical well installation costs. Table 1: Costs of Well Installation (source:
Chalk Well Drilling Ltd, Napanee, ON, 2003)
Water Quality
Checklist
Septic SystemsThe septic
system accepts wastewater from the home (sinks, shower, toilets, dishwasher,
washing machine), treats the wastewater and returns the treated effluent to the
groundwater. A conventional septic system is comprised of two components: a
septic tank and a leaching bed. Septic Tank A septic tank is
a buried, watertight container, which accepts wastewater from your house (see
Figure 4). Septic tanks can be made from concrete, polyethylene or fibreglass
and in the past were sometimes made from steel (if the property has a steel
tank, it is likely rusted through and needs replacing). Older tanks may be
smaller than those found today (the minimum current size in Ontario is 3,600 L
(952 US gal). Current tanks have two compartments, while older tanks may only
have one compartment. Solids settle to the bottom of the tank to form a sludge
layer, and oil and grease float to the top to form a scum layer. The tank should
be pumped out every three to five years or when 1/3 of the tank volume is filled
with solids (measured by a service provider such as a pumper). Some
municipalities require that septic tanks be pumped out more frequently.
Bacteria, which are naturally present in the tank, work to break down the sewage
over time.
Leaching Bed The wastewater
exits the septic tank into the leaching bed—a system of perforated pipes in
gravel trenches on a bed of unsaturated soil (minimum 0.9 m/3 ft. - see Figure
5). The wastewater percolates through the soil where microbes in the soil remove
additional harmful bacteria, viruses and nutrients before returning the treated
effluent to the groundwater. In cases where there is more than 0.9 m (3 ft.) of
unsaturated soil from the high water table or bedrock, a conventional system
is used, where the network of perforated drainage piping is installed either
directly in the native soil or in imported sand if the native soil is not
appropriate for treatment. In cases where the groundwater or bedrock is close to
the surface, the leaching bed must be raised 0.9 m (3 ft.) above the high water
table or bedrock. This is called a raised bed system.
Alternative
Systems Under certain
site conditions such as limited lot area, high groundwater table or poor soil
conditions (clay or bedrock for example), a conventional system will not provide
sufficient treatment of the wastewater. Under these conditions, it is often
possible to install an alternative treatment unit. The two most common types of
alternative treatment units are trickling filters, where the effluent from the
septic tank trickles through an unsaturated filter media (such as peat or a
textile filter), and aeration systems, where the effluent from the septic tank
passes through an aerated tank. Alternative
treatment units provide a higher level of wastewater treatment, allowing the
effluent to be discharged to a smaller area than in a conventional leaching bed.
Effluent from an alternative treatment unit can also be discharged to a shallow
buried trench, which is a pressurized pipe system 15 cm (6 in.) below the ground
surface. In most provinces homeowners with alternative treatment units are
required to have a maintenance contract with a service provider to inspect and
maintain their systems. Inspecting
the Septic System You should have
the septic system inspected by a certified on-site system professional (such as
a certified installer or engineer) prior to purchasing the home. Call your local
municipal office, public health office or Ministry of Environment office for a
list of qualified professionals. Inspections can cost anywhere from $50 for a
simple file search to $500 for a complete inspection of the tank and leaching
bed. The inspection
should include: a discussion with the homeowner, a review of the system permit,
a tank inspection, a leaching bed inspection and a house inspection. System
Replacement or Repair A septic system
should last anywhere from 20-25 years, or even longer, if it is properly
installed and maintained with regular pump-outs every three to five years. The
cost of system replacement can vary between $12,000 to over $20,000 depending
upon site conditions and local market conditions. The cost of system repair can
vary from $500 for line flushing to $1,000 for a new septic tank to over $6,000
to replace clogged leaching bed lines (tile lines). Questions to
ask the homeowner:
Permit Review
Checklist The septic
system permit can be obtained from the homeowner or the local municipal,
Ministry of Environment or public health office, depending on the jurisdiction.
There may not be a permit for older systems.
Tank
Inspection Checklist NOTE:
Never enter or stick your head into a septic tank. Dangerous gases are present
in septic tanks, which can be lethal, even after the tank has been pumped out.
Leaching Bed
Inspection
Indoor
Inspection Checklist
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