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Private Well Water

CAUTION: Confined Spaces

Small, enclosed spaces such as a cistern, septic tank, some farming and industrial equipment, well (dug / bored wells) or a well pit, may be considered Hazardous Confined Spaces and should never be entered by anyone other than a trained professional.


For more information on Hazardous Confined Spaces please visit:


Do you own a private well? Test your drinking water for bacteria at least three times per year

Why should you test your well water?

Drinking water that has harmful germs in it can make you sick. These germs can give you stomach cramps and/or diarrhea as well as other problems. The only way to make sure that your water supply is safe to drink from is to test it regularly. Testing for bacteria is free, and sample bottles are available at the Health Unit. (It is also recommended that you have your well water tested for nitrates. A list of private laboratories is available at the Health Unit, or you can consult the Yellow Pages.)


Testing your well water

  • Testing your well water for bacteria is free This includes testing for both total coliform bacteria and E.Coli bacteria.
  • Test your well water at least 3 times per year. We recommend testing in the spring, summer, and fall. Conditions change throughout the seasons and regular testing is important to make sure you aren’t drinking contaminated water!
  • Be sure to test your water after any repairs to your well, if your well hasn’t been used for several weeks, if there is flooding in the area, or if you notice a change in your water (e.g. smell, taste, or colour).

Water sample pick-up and drop-off locations

Free sample bottles are available at the Haldimand-Norfolk Health Unit office locations. Pick up bottles and drop off your water samples for testing at any of the locations listed below.

12 Gilbertson Drive
Simcoe, Ontario
519-426-6170 or
100 Haddington St
Caledonia, Ontario
117 Forest Street East
Dunnville, Ontario

Water sampling instructions are included with your water sample bottle and can also be found here: Testing your drinking water

Understanding your water test results

Click here to learn how to interpret your water sample results: Testing your drinking water

Maintaining your well

Regular well maintenance is important for protecting well water quality. If wells are not properly maintained, the water can be easily contaminated.

  • Inspect your well regularly.
  • Make sure the sanitary seal or well cap is properly sealed so that surface water cannot enter your well.
  • Seal joints, cracks, and connections in the well casing.
  • Direct surface water so that it drains away from the well casing. Earth should be mounded around the well and graded away from the well to prevent surface water from accumulating.
  • Check your well pump and distribution systems regularly.
  • Ensure your well is not located close to a septic tank, weeping tile bed, manure pile or other source of contamination.
  • Make sure dug or bored wells are not located close to a ditch, stream, pond or lake.
  • Investigate any changes in well water quantity or quality (e.g. colour, taste, and odour) immediately by visually inspecting your well and testing your well water.
  • Make sure any abandoned wells are sealed to prevent pollution of groundwater and any safety hazards. It is recommended a qualified professional be hired for this

Disinfecting your well

Disinfect your well if you have had an adverse sample result.

If your well is contaminated, sometimes a one-time (shock) chlorination of your well will make it safe again. This procedure is not recommended if the well is dug (because dug wells are open to contamination) or if there is a known source of contamination. In these cases, you need a more permanent solution such as a new well or treatment device such as a chlorinator or an ultraviolet light. Consult a licensed well driller or plumber for help. Similarly, if shock chlorination does not work, consider adding a treatment device or constructing a new well.

Dug wells, 1 m (3 ft.) in diameter: Add 1 l (1 qt.) of household bleach for every 1.5 m (5 ft.) of water depth.

Drilled wells, 15cm (6 in.) in diameter: Add 85 ml (3 oz.) of household bleach for every 7.5 m (25 ft.) of water depth.

Well points, 5cm (2 in.) in diameter: Add 85 ml (3 oz.) of household bleach for every 3 m (10 ft.) of depth.

Do not drink the water until you receive satisfactory sample results.

  1. Add regular chlorinated household bleach (not lemon-scented) to the well. If you do not know how deep the water is in the well, use the well depth to estimate how much bleach to add.
  2. Disconnect filters, run water through all taps and let sit for 12 hours.
  3. Run the treated water through an outside hose away from the septic system until you no longer smell chlorine.
  4. Resample in 48 hours. Three satisfactory samples collected one to three weeks apart indicate a bacteriologically safe supply.

Recommendations for daily activities when your water is unsafe to drink

If you receive an adverse sample result and you are disinfecting your well, this means your water is unsafe to drink.  You can:

  1. Use bottled water.
  2. Bring water to a rapid rolling boil for one minute.
  3. Add 1.25ml (8 drops of ¼ tsp) of unscented household bleach per 4.5 L (1 gal.) of water. Mix together and allow this to stand for 15 minutes (note: this treatment will not kill parasites).

Drinking: Bottled water is recommended, but boiled water and treated water can also be used.

Hand washing: Use bottled, boiled or treated water or use the usual supply for hand washing, followed by an alcohol-based hand sanitizer.

Food preparation: Use bottled, boiled or treated water to make juice or formula or to wash ready-to-eat foods such as fruit and vegetables. If the food will be boiled at a rolling boil for one minute during the cooking process, it is not necessary to use treated water. Do not use ice cubes made with the unsafe water.

Bathing/showering: Adults may continue to use the usual supply, as long as no water is swallowed. After you bathe or shower, follow the above procedure for hand washing. Give
sponge baths to children using treated water.

Brushing teeth: Use bottled, boiled or treated water.

Laundry: Use your usual source of water.

Dish washing: Use bottled, boiled or treated water.

Pets: Use bottled, boiled or treated water.

Livestock: Consult a veterinarian regarding water for livestock.

For more information call the Haldimand-Norfolk Health Unit at 519-426-6170 or 905-318-6623 and a Public Health Inspector would be happy to speak with you.  

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