Well and Cistern Maintenance for Residential Settings

Test your water reminders

Well water

For those who obtain water from wells, it's important to make sure the water is clean and safe to drink.

Water may contain many microorganisms like E. Coli and Campylobacter that can make people sick, give you stomach cramps or diarrhea. In some cases, it can be life threatening.

Frequent sampling and testing of your drinking water determines the quality of your water supply.

Testing and inspection
Wells should be tested seasonally (spring, summer, fall and winter). Learn how to take a water sample. Free testing bottles can be picked up at all Public Health locations and most town halls.

If regular seasonal samples cannot be taken, then three samples, one to three weeks apart should be obtained. A single sample is not representative of the quality of your well water. You can test as often as you want.

In addition to regular tests, well water should be tested immediately after:
- Any repairs
- The well has not been used for long periods of time, such as seasonal residences
- Flooding
- There has been a change in the surrounding land use
- There is any change in its clarity, colour, odour or taste
Bacterial testing does not provide information on the chemical water quality of your well water supply. If you're concerned about chemical contamination, you can have your water tested for chemicals by a private laboratory at your own expense.
Getting a bad result
Don't use water that has tested positive for Total Coliform or E.Coli for:
- Drinking
- Making infant formula and juices
- Cooking,
- Making ice
- Washing fruits or vegetables
- Brushing teeth
- Bathing or showering
If you want to continue to use your well water, bring it to a rolling boil for at least one minute. Your boiled water supply should always be refrigerated until it is used. Consider using alternative water sources, such as bottled water or municipal supply if available.

Handwashing

Use bottled, boiled or treated water, or wash your hands normally and then use an alcohol based hand sanitizer available at your local pharmacy.

Food preparation

Use bottled, boiled or treated water to wash ready-to-eat foods, such as fruits and vegetables, and to make juice.

Water for preparation of food that needs cooking of five minutes or longer does not have to be boiled or treated previously. Discard ice cubes made with contaminated water.

Bathing and showering

Adults may continue to shower as long as no water is swallowed. Sponge baths are recommended for children instead of tub baths. Use a safe supply of water if possible. After you bathe or shower, wash your hands in safe water.

Brushing teeth

Use bottled, boiled or treated water.

Laundry

Continue to launder clothes as usual.

Dishwashing

Use bottled, boiled or treated water.
Disinfection and filtration
If test results show an unacceptable level of Total Coliforms or E. coli, the well must be treated and, if possible, find and eliminate the source of contamination. Disinfection can be done using household bleach. Mix the bleach with several litres of water before pouring it down your well.

Drilled well

142 mL (5 oz.) of bleach for every 7.5 metres (25 feet) of well depth

Dug well

1 litre (1 quart) bleach for every 1.5 metres (5 feet) of well depth

Calculate your well disinfection rate.
1. Run water through all taps until you can smell the bleach. Do not use the water for 12 hours.
2. After 12 hours, run the rest of the treated water through an outside hose away from the septic tank system. Stop running the water when the smell of bleach is gone.
3. Wait at least two days before collecting a sample for testing.
4. After completing this procedure, obtain three consecutive satisfactory samples to ensure your drinking water is safe. These should be collected one to three weeks apart. Assume your water is unsafe until you get these three satisfactory results.
Filtration

It's recommended to have a treatment system installed to ensure your water remains safe for consumption.
Well construction
It's important for homeowners to always use a licensed well contractor and understand their legal obligations as a private well owner. This includes requirements for well construction, maintenance, notification, documentation, abandonment and licensing under the Well Regulation.

Well construction, licensing and maintenance resources
The Ontario Wells Help Desk is also available at wellshelpdesk@ontario.ca or toll-free at 1-888-396-9355 (Ontario residents only).

Cistern water

Some rural residents get their drinking water from a reservoir or cistern typically made from concrete. A cistern is used most often in areas where wells don't provide sufficient water or have historically produced water that is unsuitable for drinking.

A properly constructed cistern filled with municipally treated water delivered by an approved water hauler should provide water that is safe to drink. A cistern still needs periodic inspection, cleaning and disinfection. Poorly maintained cisterns are easily contaminated.

Testing and inspection
- Use a cistern made from a material suitable for holding drinking water
- Maintain the cistern in a way that prevents the entrance of bugs, rodents, and surface water runoff
- Inspect the cistern annually for sediment, bio-film (slimy coating), debris, cracks and seepages, ill-fitting lids, and broken vent screens
- Don't direct rainwater into the cistern. Bacteria from bird and animal droppings, dust, leaves and chemical residues from roofing materials will contaminate the cistern.
- Refill the cistern with potable drinking water only. Potable water haulers typically get their water from a municipal water supply and are inspected by Niagara Region Public Health. See water hauler inspection reports.
Cleaning
Empty and clean the inside of the cistern every one to two years. You can:
- Remove sediment and debris
- Check and repair any cracks or seepages
- Remove any bio-film
- Repair any damage
A cistern that needs entry into it for maintenance and cleaning should be considered a confined space. Hazardous gases or low oxygen levels may be present. Only individuals trained in confined space entry should enter a cistern

After cleaning, disinfect the cistern.
Disinfection and filtration
1. Disinfect the cistern:
2. Add four ounces of household (5.25 per cent) unscented bleach per 1,000 gallons of water
3. Mix the bleach and water with a large clean object
4. Run each water line (one at a time) in the house until a chlorine odour is noticed. This includes flushing all toilets, and running all baths and showers. If no odour is noticed, add a little more bleach to the cistern.
5. Let stand overnight (minimum 12 hour contact time required)
6. After at least three days, submit a water sample for bacteria testing
7. Do not drink the water, or use it for brushing teeth or washing fruits / vegetables, until you have received your test results. The water should be safe for bathing, showering, laundry and toilet flushing.
8. It is recommended that at least a seven day supply of drinking water (bottled water) be arranged before starting this process (typically 1.5 litres per person per day should be enough)
Filtration

It's recommended to have a treatment system installed to ensure your water remains safe for consumption.
Bacterial testing
Get free sample kits for bacteria testing from municipal service centres and Public Health.

Sample freshness and temperature control is essential for proper testing for bacteria. We recommend you take the sample on your way to the drop off site. If that's not possible, bring the sample to the drop-off location within 12 hours of collection and keep it cool in transit and in storage.

Samples must reach the testing laboratory within 48 hours of collection time.

Testing

Cisterns should be tested seasonally (spring, summer, fall and winter).

If regular seasonal samples cannot be taken, then three samples, one to three weeks apart should be obtained. A single sample is not representative of the quality of your well water. Continue to sample a minimum of four times per year. You can test more often if you want.

The best time to sample cistern water is when the probability of contamination is greatest. This is likely to be in the early spring, after an extended dry spell, following heavy rains or after lengthy periods of non-use.

In addition to regular tests, well water should be tested immediately after:
- Any repairs / replacements
- The cistern has not been used for long periods of time, such as seasonal residences
- Flooding
- There has been a change in the surrounding land use
- There is any change in its clarity, colour, odour or taste
Test results

If sample test results indicate the drinking water supply is unsafe, stop drinking it.

It's recommended to inspect the cistern and resample and test the water. If the re-sample results show the water is unsafe for drinking and the cistern appears clean and maintained, disinfect the cistern. Make sure you're testing your water properly.

Chronic unsafe test results indicate a likely need to install a permanent disinfection device, such as a chlorinator or ultraviolet system. A professional should be consulted for assistance.