Buying a Home With a Well
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 systems before purchasing a home.
These are common types of wells for Ontario:
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 are prone to contamination from surface water infiltration and to water shortages.
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 example 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 provide a safer source of drinking water.
Standard 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 the 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 the system’s prime and pressure.
- Pumping system — includes the 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 typically use centrifugal pumps, which are located out of the well, most likely in the basement or a pump house.
- Surface protection — prevents surface water and contaminants from entering the well. It includes a watertight seal placed around the casing (annular seal), a 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 home 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.
Well Record — Obtain a copy of the well record from the owner or the Ministry of the Environment. This should include a location of well, date of well drilling, depth, and diameter of well, static water level, pumping water level, recommended pumping rate and the recommended pump setting.
Location — A well should be located at least 15 m (50 ft.) from any source of contamination if the casing is watertight to a depth of 6 m (20 ft.); otherwise, the separation distance should be at least 30 m (100 ft.). Sources of contamination include septic systems, manure storages, fuel storages, agricultural fields (manure or fertilizer runoff), and roads (salt runoff). Wells should be located at least 15 m (50 ft.) from a body of water.
Well Cap — The cap should be at least 0.3 m (12 in.) above the ground. The well cap and seal should be securely in place and watertight. A locking cap would give some added security against tampering. Well caps are on drilled wells, and well covers are on dug wells. Both types should be inspected.
Well Casing — No cracks or settling of the casing should be visible. The ground should slope away from the casing.
Drainage — Surface water should drain away from the well and water should not pond around the well casing.
Well Pump — The well pump and distribution piping should be in good condition.
Grass Buffer — A permanent grass buffer of a minimum 4 m (12 ft.) width should be maintained around the well head. Fertilizers and pesticides should not be applied to the grass buffer.
Abandoned Wells — All abandoned wells on a property must be decommissioned (plugged) by a licensed well contractor. Ask the owner if there are any abandoned wells on the property and if they have been properly decommissioned.
Inside the House — Check for sand or grit in the faucet strainer that indicates a corroded well screen. Verify that the pressure tank reads between 250 to 400 kPa (40 and 60 psi). Ensure that the check valve (or foot valve) can sustain the system pressure by drawing no water for 30 minutes to an hour and monitoring the pressure. The pressure should not drop nor should the pump start during this dormant period.
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:
- The pumping rate is higher than the groundwater recharge rate.
- The water table (level of saturated water in the soil) has dropped below the pump suction or inlet.
- The well screen has become plugged by fine sand, chemical precipitation, bacterial fouling or corrosion.
- If a well vent becomes blocked, a negative pressure may occur (in the well) during drawdown and reduce or stop the pump from drawing water.
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 of the home
There are a few sources of information to help determine if a well can produce a sufficient quantity of water:
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. 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 considerably depending upon the amount of precipitation.
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 that 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.
Water Quantity Checklist
Ask the Sellers, neighbours or a local well contractor if there have been any problems with the well or area wells running dry. Verify the depth of the well and pumping rate from the well record. A surface well is more likely to run dry in times of drought. Have a licensed well contractor conduct a recovery test, if necessary.