All About Wells


Your well taps into one of nature’s precious resources – cool, clean groundwater!
You and your family depend on this every day for cooking, washing and supplying safe drinking water.
As a well owner it’s your job to understand the basics of well maintenance and operation and to take the necessary steps to keep your well water safe.

Well Basics
Your well gets its water from an underground water source called groundwater, which originates from surface water and precipitation, including rain and melting snow that infiltrates the earth, filling open spaces in the rock and soil.
Saturated layers below the water table that store enough ground water to supply a well are called aquafiers.
Groundwater can also be subject to contaminants that infiltrate the soil such as leaking fuel, storage tanks and malfunctioning septic systems. Poorly constructed or deteriorating wells can be a direct pipeline for contaminants to the aquafier.
Depending on the type of soil or rock groundwater may be filtered and be very clean. But once an aquafier is contaminated, it can take very long time to recover.

Locating a new well
If you are constructing a new well, think carefully about the best location. This would be a high point of land with good access and separation from potential contaminants.  You want the run-off and contaminants to drain away from the well head rather than towards it.  You can contact a Ministry of the Environment – licensed well contractor to locate a well on your property.

Wells and well equipment must be sited so they can be easily accessed for cleaning, treatment, repair and testing.
Wells must be located a safe distance from sources of contamination such as fuels, pesticides, tanks, chemicals, road salt, septic systems , gardens, manure, livestock, roads and driveways.
Wells must be at least 15 meters (50’) for drilled wells and 30 meters (100’) for all other wells away from potential contaminants. These minimum distances do not guarantee safety.

Well Construction
Water must infiltrate and pass down through the soil and rock before it can reach the aquafier from which your well gets its water.

Well Casing:   New wells should be lined with a watertight casing designed to keep out contaminants. This casing must extend to the   appropriate depth (to the aquafier) from which the well draws water (normally at least 6 meters (20’) below grade. The casing must also extend at least 40 centimeters (16 inches) above the finished grade to help prevent contamination by surface water and run-off.

Well Pits:
   Commonly used prior to 1985 to protect water line connections from freezing, however well pits are no longer considered safe because they often fill with surface water and debris leading to contamination. On new wells the well casing must extend above ground level and a pitless adapter is used to provide a sealed waterline entry at depth so that water lines are protected from freezing.

The Annular Seal: The annular seal serves as a barrier to run-off, surface water and near-surface waters that could travel down the outside of the casing and contaminate the aquafier. When your well is drilled the hole in the ground is bigger than the well casing resulting in a gap (annular space). This space must be filled with a watertight sealant that does not shrink or crack under the ground.

Well Cap: It is required to cap your well with a commercially manufactured vermin-proof well cap. Modern caps have rubber gaskets and screened vents inside to prevent entry of vermin, insects and decaying plant material.

Upgrading your well
Upgrade or construct a new one? If,

  • there are any water quality problems with your existing well,
  • its badly located close to permanent sources of contamination or at the risk from flooding
  • not producing adequate water supply or
  • cannot be upgraded for technical or regulatory reasons

One option is to drill a new well.

Decommissioning or Sealing your well
Any unused or unmaintained well that hasn’t been properly plugged and sealed poses health and safety hazards for animals and humans and threaten the groundwater that supplies your well and possibly your neighbours well.
It is your responsibility to ensure that your unused wells are properly plugged and sealed.
Don’t try to seal your own well it, it’s not as easy as it seems. If you simply fill your unused well with sand, gravel, stones, debris or garbage you won’t prevent the flow of surface water or run-off into the well and the material used may even contribute to contamination of your groundwater.

If an unused or unmaintained well is on your property, you are legally responsible for ensuring that it is plugged and sealed properly. Hire a Ministry of the Environment professional who has the expertise and equipment to do the job properly.

Protecting your well water
As a well owner you need to make a regular schedule for well maintenance

  • eliminate or reduce using contaminants
  • inspect your well regularly and keep it in good working order
  • test your well water regularly and respond to any issues
  • install a backflow prevention device

You can do this by walking the grounds within a 100’ radius of your well. Look for potential threats or changes that could affect your well.

Keep these contaminants away from your well:

  • pet and livestock waste
  • gasoline, diesel and home heating fuels
  • pesticides and fertilizers (chemical or natural)
  • paint, solvents, fire starter, de-icer and any other substances you don’t want in your family’s drinking water.

Inspecting your well

  • keep your well accessible and clear from brush, debris or any other obstruction
  • check the well cap for signs of cracking or damage and get it replaced immediately if there’s a problem.
  • The well cap should be firmly attached to the casing, the vent should face the ground and be properly screened to keep out insects. Only air should enter. Clean the air vent regularly to remove debris and moisture.
  • Look for problems with the sealant used to fill the annular space between the drilled hole and the well casing. A depression in the found around the edge of the casing can indicate that there sealant has shrunk, collapsed or cracked.
  • Look for any external signs of damage, animal infestation, stains, cracking or discolouration coming from the casing joints
  • Remove the cover from your well pit and look for water, debris, vermin etc. Do Not enter the pit or breathe the gases which may fill the pit. The pit should be clean and dry so if there is water or other debris, your well is at risk of contamination.

Possible Contamination

What could be wrong with your water?
Even though your water may appear to be fine, there may be contaminants that you can’t see, smell or taste.
Drinking contaminated well water can make you and your family ill, even fatally.
Bacterial contamination may cause stomach cramps, diarrhea and other ailments
Chemical contamination is equally as dangerous

Total Coliforms:Coliforms are bacteria. Even a count of (1-5) may indicate the presence of harmful bacteria. A total coliform count of (6-80) is a strong indication that disease-causing micro-organisms may be present and your water is unsafe to drink.

E. coli:  is a strain of bacteria associated with human and animal fecal matter. Any detectable amount of E.coli is unsafe for drinking.

  is not bacteria but is the result of a chemical reaction from fertilizers and human or animal waste. Nitrate reduces the amount of oxygen in the blood. Infants can become sick from drinking formula or eating cereals made from water with high levels of nitrate

Sodium, Metals, Minerals, Gasoline, Oil, Fuels, Solvents and Pesticides are all things to test for if you have a suspicion, smell odours or are concerned of spills in and around your well

Water testing
To test for harmful bacteria it’s recommended that you rest your well water regularly for bacteria.
Your local health unit will provide the tests for free.
Testing is recommended at least 3 times per year.
Early spring, the day after a heavy rainfall and melting snow are all good times to take water samples. If your well water is safe under these conditions, it is most likely to be safe the rest of the year.
You should test regularly even if your water seems fine
Besides routine testing, you should also test after:

  • Major plumbing work or well repairs
  • If you detect changes in the water quality including taste, odour, and appearance
  • If regular users of the well experience unexplained health problems
  • After flooding

How to Test for Bacteria

  • Use the water sample bottle provided by your testing facility
  • Do not touch the bottle tip, inside the lid or inside the bottle
  • Do not rinse out the bottle
  • Select a non-swivel tap and remove aerators and other attachments from the tap
  • Disinfect the end of the faucet with a chlorine-water mix
  • Run cold water for 2-3 minutes
  • Fill the sample bottle to the indicator line directly from the tap
  • Replace the cap tightly and complete the form that came with the bottle
  • Refrigerate the sample after collection and transfer in a cooler if possible
  • Turn the sample and form into the health lab within 24 hours of collection

Well Disinfection
Shocking is only a temporary method of disinfection to eliminate a one-time case of bacterial contamination and should not be used routinely or repeatedly. It is not meant not to substitute for an ongoing issue with your well.
When shocking your well, you should consult your local public health unit for detailed instructions.

Treatment Options
If your water is contaminated, it’s best to remove the source than to treat the water, however if the problem is continuous there are a number of water disinfection systems available.

Each system requires routine maintenance and regular testing of your water is required.

Chlorinators continuously add chlorine to your water. These must be checked often to ensure the right amount of chlorine is being added Ultra-Violet (UV) light filters kill bacteria, viruses and intestinal protozoa. The light must be replaced yearly

Distillers:  boil water and then condense the vapour and collect it in another compartment. Bacteria and minerals are removed.
Ozonators:  inject small amounts of ozone gas into water to kill most bacteria

Reverse Osmosis:  removes some chemicals nut not bacteria. It works by passing pre-filtered water through a membrane removing inorganic chemicals such as nitrates and chloride. Reverse osmosis wastes large amounts of water, which can be a concern if the water supply is limited or there is stress on the septic system. It’s ideal to only use RO for drinking water.

Activated Carbon Filters: can improve taste and odour and remove organic chemicals
Ion Exchange Water Softeners  remove calcium and magnesium hardness

Further Resources:         a website for private well owners                   Ontario Ground Water Association        Ontario Ministry of the Environment            an education, resource and research centre for private well owners

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