Information on private wells |
Learn more about how wells work, how they get contaminated and treatment options. |
How to sample your well water for bacteria |
Bacterial testing for private wells is performed free of charge by the Ontario Ministry of Health Public Health Laboratory at 2380 St. Laurent Blvd. Sample bottles are available for pickup at that laboratory, and at water testing pickup and drop-off locations.
- Obtain a water sample bottle.
- Plan to sample your well water when you are sure it can be delivered to a drop-off location within 12 hours of the collection time.
- Remove any aerator, screen, or other attachment from your kitchen faucet. If you cannot do this, take a sample from an inside faucet with no aerator, such as the bathtub. Do not take a sample from an outside faucet or the garden hose.
- Turn on the cold water and run for two to three minutes to remove standing water.
- Disinfect the end of the faucet spout with an alcohol swab, or a diluted bleach solution (1 part household bleach to 10 parts water).
- Turn on the cold water again and run for three minutes before sampling. Remove the lid of the sample bottle. Do not touch the inside of the lid, put down the lid, or rinse out the bottle.
- Fill the bottle to "fill line" directly from the tap without changing the flow of water. Do not touch the bottle lip. Replace cap tightly.
- Samples must be refrigerated after collection. During transportation, put bottle in a cooler if possible.
- Remove ONE of the bar code stickers from the bottle and attach it to the blue card that came with your water sample bottle. This bar code is your PERSONAL IDENTIFICATION NUMBER (PIN). You will need it to get your results over the phone.
- Return the sample and completed form within 12 hours of collection. If your form is incomplete, the laboratory will not test your sample, and you will need to submit another sample with another form.
Results
You can usually get your test results two to four business days after you drop off your sample.
Test results are available by:
- Telephone: Call 1-877-723-3426 and key in the barcode number from the sample bottle (PIN) to hear an automated message with your test results and interpretation; or
- Mail: If you indicated on the form that you want the report mailed or made no choice, the report will be mailed to the name and address written on the form; or
- In-person at 2380 St. Laurent Blvd: If you indicated on the form that you will pick up the report at the laboratory, show your photo identification at the reception desk during regular operating hours.
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Well water testing - pick up and drop off locations |
OPH has established permanent sites across Ottawa where well owners can drop-off their water samples and pick up new bottles for future testing. Residents wishing to pick up water bottles and drop off their samples may do so during regular business hours at the following locations:
In the city - Monday to Friday Statutory holiday schedule change: Closed on Monday October 14, 2024
- 101 Centrepointe Drive, Ben Franklin Place Client Service Centre: Monday to Thursday 8:30 am to 4 pm and Friday 8:30 am to 11 am
- 2380 St. Laurent Boulevard Public Health Ontario Laboratory: Monday to Friday: 8 am to 4 pm
Rural - Tuesday Only
- 1220 Colonial Road - Navan. JT Bradley Store - Tuesday: 6 am to 9 pm
- 6045 Bank Street - Greely. Foodland Greely - Tuesday: 24 hrs
- 5669 Osgoode Main Street. Osgoode Foodland - Tuesday: 6 am to 11 pm
- 5911 Perth Street - Richmond. King's Your Independent Grocer - Tuesday: 8 am to 9 pm
- 255 Centrum Boulevard. Orléans Client Service Centre - Tuesday: 8:30 am to 4 pm
- 8243 Victoria Street. Metcalfe Client Service Centre - Tuesday: 8:30 am to 4:30 pm
- 5499 South River Drive. Manotick Library - Tuesday: 10 am to 8 pm
- 1096 Bridge Street - Manotick. Rural Ottawa South Support Services - Tuesday: 8 am to 4 pm
- 7814 Lawrence Street. Osgoode Township Museum - Tuesday 10 am to 5 pm
- 6579 Fourth Line Road. North Gower Library - Tuesday: 1 to 8 pm
Rural - Wednesday Only
- 3084 Kinburn Side Road. Kinburn Darvesh Grocery - Wednesday: 7 am to 8:30 pm
- 131 Constance Bay Road. Constance Bay Pharmacy - Wednesday: 10 am to 7 pm
- 3798 Dunrobin Road. Nicholls General Store - Wednesday: 6 am to 11 pm
- 1794 Dunrobin Road. MacEwen Gas Dunrobin - Wednesday: 5:30 am to 11 pm
- 3911 Carp Road. Carp Library - Wednesday: 10 am to 8:30 pm
- 5670 Carp Road. West Carleton Community Complex - Wednesdays: 8:30 am to 4 pm
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What the test results mean
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If you need help interpreting the results, please contact Ottawa Public Health at 613-580-6744 and speak with a Public Health Inspector.
Bacteriology interpretation
Drinking water is tested for the presence of two groups of bacteria: Total Coliforms and E.coli (Escherichia coli).
Total Coliforms are a group of bacteria commonly found in animal waste, sewage, soil and vegetation. They are also found in the intestines of animals and humans. Total Coliforms are not likely to cause illness, but their presence indicates that your water supply may have been contaminated by more harmful microorganisms present in surface water seeping into your well.
E.Coli bacteria are normally found only in human and animal digestive systems. The presence of these bacteria in your drinking water, usually means that human and animal waste is entering your well from a nearby source such as a local septic system or manure. Although most strains of E. coli bacteria are harmless, the presence of E. coli in well water indicates fecal contamination. This means there could be harmful bacteria, viruses, and parasites in your well water.
Results
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What it means?
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What to do?
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Total coliform=0 E. coli = 0
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No significant bacterial contamination was found
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Continue to test your drinking water on a regular basis to see if there are any changes in your drinking water quality.
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Total coliform= less than or equal to 5 E. coli = 0
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No significant bacterial contamination was found
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Safety difficult to assess on the basis of a single test. Resample as soon as possible. Follow the Public Health Ontario water sampling procedures.
Three samples taken 1-3 weeks apart are needed to determine the stability of the water supply.
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Total coliform= more than 5 E. coli = 0
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Significant bacterial contamination was found
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Stop using your well water, use bottled or boiled water.
If you want to continue to use your well water, bring it to a 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 used.
Disinfect the well and resample. Follow proper disinfection procedures.
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Total coliform= 1 or more E. coli = 1 or more
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Indicates bacterial contamination from animal or human feces
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Stop using your well water, use bottled or boiled water.
If you want to continue to use your well water, bring it to a 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 used.
Disinfect the well and resample. Follow proper disinfection procedures.
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NDOGN - No Data: Overgrown with Non-target
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Only "non-target" bacteria commonly found in the environment are visible during the test process. They are not usually a health hazard but can interfere withthe detection of Total Coliforms and/or E. coli
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Stop using your well water, use bottled or boiled water.
If you want to continue to use your well water, bring it to a 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 used.
Disinfect the well and resample. Follow proper disinfection procedures.
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NDOGT - No Data: Overgrown with Target
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A large number of bacteria present and Total Coliforms and/or E. coli are visible to the analyst but it is dificult to determine exactly how much
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Stop using your well water, use bottled or boiled water.
If you want to continue to use your well water, bring it to a 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 used.
Disinfect the well and resample. Follow proper disinfection procedures.
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Information obtained from Public Health Ontario
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What to do if your well water is contaminated
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If you want to continue to use your well water, bring it to a rolling boil for at least one minute and let it cool before using.
Use tap water for: | Use bottled or boiled water for: | Do not use the water for: |
- Flushing toilets
- Washing clothes, linens and bedding
- Taking showers (for adults and older children)
- Washing floors
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- Drinking
- Brushing teeth
- Making food and baby formula
- Sponge bathing babies and young children (after cooling the water)
- Making coffee
- Making ice
- Washing fruits and vegetables
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- Kitchen and other household water filters
- Ice makers directly connected to the affected water supply
- Children's water play stations (e.g. wading pools and water tables)
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How to disinfect a well
A residential private well owner can work on and disinfect his or her own well. However, there are some safety considerations when working on a well and many technical steps needed to properly clean and disinfect a well. Therefore, the well owner should consider retaining the services of a qualified professional or qualified technician.
You can disinfect your well contaminated with bacteria by "shock-treating" it with ordinary chlorinated household bleach containing 5.25 per cent sodium hypochlorite. In accordance with the Ministry of Conservation and Parks – “Well Disinfection of the Water Supply Wells - Requirements and Best Management Practices”, Ottawa Public Health recommends that the well water and equipment is chlorinated by dosing the well water to a concentration of at least 100 ppm of free chlorine. Don't use scented bleach for this purpose. Buy fresh bleach to do this because the chlorine in bleach is unstable and evaporates over time.
- Store enough clean water to meet household needs for a minimum of 12 hours.
- Bypass or disconnect any carbon filters, water softeners or other water treatment devices or else any pipes located past these filters will not be disinfected. Replace the filters once chlorination is completed. Highly chlorinated water can damage treatment units. It is important to follow the manufacturer’s recommendations to ensure treatment systems are properly disinfected. Be sure that the hot water tank’s heat source is shut off.
- Estimate the chlorine necessary to disinfect the water in the buildings plumbing including the hot water tank (calculator provided), and the chlorine necessary to disinfect the water in the well water column (calculator provided). Add them together.
- Drain all water out of plumbing including the hot water tank prior to dosing.
- Mix the chlorine required to disinfect the well in 25 litres (5 gallons) of water. Note: The well calculator accounts for the extra 25 litres of water used for mixing.
- Pour the mixture into your well.
- Thoroughly mix the chlorine solution and the water throughout the well column. This can be accomplished by attaching a hose to a tap and running water from the well through the hose and back into the well.
- Start the pump and bleed air from the pressure tank. Open all water taps one at a time, including outside hose bibs and cold and hot water taps. Allow the water to run until a chlorine smell is detected from each faucet then turn off each tap. Since chlorinated water can damage the action in a septic system, chlorinated water should not be allowed into the building’s sewage system.
- If a strong chlorine odour is not present, return to step 4, add half the amount of chlorine used for the initial treatment to the well and repeat steps 5 and 6.
- Let the chlorinated water stand in the system for 12 to 24 hours.
- Start the pump and run water through the outside hose away from vegetation until the strong smell of chlorine disappears. Make certain that the water does not enter any watercourse. Finally, open the indoor taps until the system is completely flushed. Taps or fixtures discharging to the septic tank systems should be temporarily diverted to an outside discharge point to avoid affecting the septic system.
- Wait 48 hours and then sample the water using the instructions and bottle provided by the laboratory. Two consecutive "safe" tests, performed on samples obtained over a period of one to three weeks, will probably indicate that the treatment has been effective.
- If the above steps do not alleviate the problem, it is recommended that the source of the ongoing contamination be determined and corrected, possibly with professional help.
Information obtained from Public Health Ontario
Resample your drinking water after corrective actions have been taken. As a private well owner, you are ultimately responsible for the system maintenance, operation and quality of your water. If your drinking water quality does not improve, you may need to have your well inspected by a licensed well contractor who will be able to provide you with options to address the issue.
You could also install a treatment system to remove bacteria. For treatment options, consult with a water treatment professional.
Drilled wells |
A well with a diameter of six inches (15 cm): Add five ounces (148 mL) of household bleach for every 25 ft (7.6 m) of water depth.
Well Depth (feet)
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Well Depth (metres)
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Bleach Volume (fluid oz.)
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Bleach Volume (ml)
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25
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7.5
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5
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148
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100
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30 |
20 |
592 |
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Dug wells |
A well with a diameter of three feet (1 m): Add one quart (one litre) of household bleach for every five feet (1.5 m) of water depth.
Well Depth (feet)
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Well Depth (metres)
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Bleach Volume (litres)
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5
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1.5
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1
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10
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3
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2
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Sand Point Well (well point) |
A well with a diameter of two inches (5 cm): Add about one quarter ounce (6 ml) of household bleach for every 10 ft (3 m) of water depth.
Before starting the disinfection process, the outside of the sand point well (well point) and all associated equipment should be cleaned and disinfected. Homeowners can use disinfectant wipes or alcohol swabs. Unscented household bleach can be introduced in the well by removing the well cap. Ensure your pump does not run dry.
Using a drain plug opening, pressure gage opening outlet pipe, or other opening into the pressure tank, add chlorine bleach or other chlorine into the pressure tank, so that the water in the tank contains approximately 50 ppm free chlorine. This will take approximately 3 (three) tablespoons, or 1 ½ ounces of bleach for each 10 (ten) gallon of tank capacity (a 50-gallon tank, for example, will require approximately ¾ (three quarters) of a cup of bleach.
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Private wells - Drinking water safety during and after a power outage |
Power outages can disrupt private well water drinking supplies. Visit our Severe weather page for more information. |