Private Wells

Taking a water sample

Test your drinking water for the presence of harmful bacteria at least three times a year.

Step 1

Use a water sample bottle with attached form. You can get these from the Health Department or Ontario Ministry of Health and Long-Term Care Public Health Laboratory.

Step 2

Remove all attachments from the faucet including the aerator, rubber washer and any hoses.

Step 3

Be sure to disinfect the tap with alcohol or plain bleach (5.25 per cent sodium hypochlorite).

Step 4

Run cold water tap for a minimum of five minutes.

Step 5

Unscrew cap from water sample bottle. Be sure not to contaminate the inside of the cap or the neck of the sample bottle with your fingers.

Step 6

Fill bottle to 200 mL water line indicated on bottle.

Step 7

Screw cap on tightly.

Step 8

Fill out the form that is comes with the water sample bottle.

Remember to write the PIN on the form so you can get your results over the phone.

Step 9

Put bottle filled with water sample inside an insulated cooler with ice pack and take everything to the nearest drop-off location.

Note: All laboratories must receive water samples within 24 hours of the sampling date. Samples received after 24 hours will not be tested.

What should I do if I suspect my well water is not safe?

• Stop using the well water and contact the Durham Health Connection Line.
• Use an alternate source of potable water (e.g. boiled water, commercially bottled water) for drinking and cooking.
• Do a visual check of your well (See the Homeowners well maintenance and inspection checklist).
• Where applicable, check the operation of installed treatment equipment (e.g. UV light).
• Consider well disinfection or the installation of long term treatment options.
• Call a licensed well technician or water treatment specialist.

If only bacteriological contamination is present and you want to continue using the water from your well, bring water to a rapid rolling boil for at least one minute and let it cool before using it for drinking, making infant formula, juices, ice or recipes, brushing your teeth, rinsing contact lenses, and washing food or dishes. Refrigerate your boiled water until it is finished. Also see Facts About ... Boil water advisories for additional information.

Note: If chemical contamination (e.g. pesticides, oil, gasoline, etc.) of your well water supply is suspected, do not boil your drinking water. Contact the Durham Health Connection Line for further advice.

To disinfect your well you should shock chlorinate the system with a high concentration of bleach.

Protect your skin from splashes from the bleach by using gloves, goggles and clothing. Never mix bleach with other chemicals.

• Follow the chart included in the Private Well Water Manual under the Shock Chilorination section for correct measurements.
• Regular household bleach (Sodium Hypochlorite 5.25 per cent) should be used to chlorinate your well. Do not use "fresh scent" bleach or other products to disinfect wells.

Be sure you have another safe, potable source of water to use during this process.

Wells require maintenance as they age. Use the Homeowners well maintenance and inspection checklist to regularly inspect your well.

Warning: Do not enter a well or well pit at any time during an inspection.

When a well is no longer in use contact the Ministry of the Environment Conservation and Parks (MECP) for advice on abandoning the well.

You should think about properly abandoning or plugging your well if:

• A new well is drilled and you are no longer using the old well.
• The water quality is bad and you need another water supply.

An Ontario Ministry of the Environment Conservation and Parks (MECP) licensed well contractor must be hired to abandon the well.

*Source: Best Management Practices: Water Wells (Ontario Ministry of Agriculture, Food and Rural Affairs/Agriculture and Agri-Food Canada)

• Facts About... Boil water advisories
• Facts About... Barium in well water
• Facts About... Lead in drinking water
• Drinking Water Indicator Bacteria and Their Significance, Public Health Ontario, October 2022