Private Drinking Water
Testing Private Drinking Water
Private drinking water sources (mainly wells or surface water) have the potential to be contaminated with bacteria, viruses, parasites, chemicals, metals and minerals. Any of these may cause illness and could be fatal. Water quality can change with the seasons and be affected by weather. Public health recommends testing at least 3 times a year, after any work is done on your well or water system and after significant weather events such as a fast thaw or severe rain storm. People who use water from private supplies should know how to test their drinking water and what type of water source they have and how to protect it.
Water bottle pick up and drop off locations in Grey Bruce have temporarily changed due to the ongoing COVID-19 pandemic.
Ontario residents who use a private drinking water system (not a municipal system) can test it for bacterial contamination free of charge. Please see the grey bruce health unit video to see how to take your water sample. Tests for other contaminants (chemicals, metals, minerals) must be completed at a private laboratory.
Nitrate testing is recommended, especially if you have an infant that will be consuming the water. Nitrates above 10 milligrams per litre of water can cause a condition known as methemoglobinemia or "blue-baby syndrome" by limiting the ability of blood to carry oxygen. High nitrate levels are usually a result of fertilizing fields or septic seepage. Tests for other nitrates contaminants must be completed at a private laboratory.
Public health inspectors can help you interpret the results of bacteriological analysis and advise you on corrective measures. Please call us at 519-376-9420 or 1-800-263-3456, or email us for assistance. Public Health Ontario has lots of information on private drinking water testing.
Water sampling and results
- wash hands before taking the sample
- remove screen, aerator or other attachments from tap.
- run cold water for 2 to 3 minutes
- disinfect the faucet with a diluted bleach solution (1 part household unscented bleach to 10 parts water)
- run cold water for 2 – 3 minutes again.
- do not touch the inside of the bottle or lid do not put the lid down or rinse out the bottle (the bottle contains sodium thiosulphate to neutralize chlorine, it may cause a reaction if ingested or inhaled).
- fill the sample bottle to the level marked on the bottle
- attach the name label found on the bag to the bottle. place the completed form in the bag provided, and wrap the bag around the bottle (fold the top of the bag over to keep the bottle in the bag).
- keep the blue card with a barcode sticker attached for your records and for calling in for results.
Water samples are sent to the London public health lab. If you have any questions about your sample submission please contact the lab.
To obtain your results:
the toll-free interactive voice response (ivr) is available 24 hours a day, 7 days a week at:
1 (877) 723-3426
tty: 1 (866) 828-2238
Key in the barcode number from the sample bottle (pin) to hear an automated message with your test results and interpretation. Please wait 3-4 days for results to be available.
If you indicated on the form that you will pick up the report at the lab, you will need photo identification and can only pick it up during business hours (see drop-off hours). If someone is picking up the report for you, they will need a potability of water release form and photo identification
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.
Coliforms. These bacteria are often found in animal waste and sewage, and soil and vegetation. If they are in your drinking water, it means surface water may be entering your well and your water may not be safe to drink.
Low levels of coliform bacteria (1 to 5) is considered safe in a private water supply, provided at least 3 samples have been taken over a six week period, the system is secure and is not subject to contamination (i.e. a dug or shore well).
E. coli (escherichia coli). These bacteria are normally found only in the digestive systems of people and animals. If they are in your drinking water, it usually means that animal or human waste is entering your well from a nearby source and your water is unsafe to drink without treatment.
If either of these organisms are found in your well water it could mean that you also have viruses or protozoa in your water. these are other tiny organisms that can cause human disease.
PHO laboratories test for the indicators of bacterial contamination (coliforms and e. coli). The sample is not tested for any other contaminants (i.e. nitrates). This means that even if your result shows there is no bacterial contamination in your drinking water, it still may be unsafe to drink. Well aware has information on how to obtain private drinking water testing. Click here for a list of licensed labs.
Please contact the Grey Bruce Health Unit for more information.
If you do not have an emergency supply of water or access to bottled water or a municipal water source, you can boil your water to kill pathogenic organisms (bacteria, viruses and protozoa). Bring water to a rolling boil for 1 minute, let it cool and store it in clean containers with lids. If the water tastes “flat” you can pour it from one clean container to another a few times to improve the taste. Use boiled water or an alternative safe source for washing fruits and vegetables, cleaning teeth, making ice, etc.
Your public health inspector may recommend that you disinfect your well. well disinfection can resolve some temporary problems and should always be done following construction of a new well or work on a well. Well disinfection is not a treatment system, if you have ongoing issues you should contact a well specialist and consider well rehabilitation. Well disinfection is an effective way of destroying bacteria, viruses and protozoa in the well and plumbing system.
See the procedure for disinfecting a well (public health Ontario) for disinfection instructions and a tool for calculating the amount of chlorine (unscented household bleach with no additives) required. If you do not know the volume of water in your well you may be able to find your well record from the moecc well record information system.
The information here is intended as a guide. If you are unsure about the process, contact a public health inspector at the Grey Bruce Health Unit or a licensed well driller who will be able to give you advice based on your well and/or carry out the process for you.
Water sources and wells
There are many sources of private drinking water in grey and bruce. The majority are wells drawing groundwater, but some use surface water from a lake or spring. well owners do have certain legislated responsibilities outlined in the wells regulation – r.r.o. 1990, reg. 903 (ontario water resources act).
Drinking water source protection includes ensuring that your well is properly maintained to prevent contamination of the source water. protecting your source water by maintaining your septic system and preventing chemical contamination are very important.
The Grey Bruce region has areas of karst limestone, where water has dissolved channels and voids into the limestone creating a path for surface water to enter and contaminate deeper aquifers in the limestone. wells in areas with limestone should be carefully assessed to determine the potential to be contaminated by surface water. for more information on water sources and well types please see the private well water manual (a quick users guide).
Water source protection
Protecting your drinking water source is important not only in providing you and your family with safe water, but also for everyone else who is drawing water from the same source. the ministry of environment and climate change governs water source protection.
- Ensure your well is properly constructed and located to prevent the direct entry of surface water.
- Periodically inspect your well to ensure that there are no obvious problems (i.e. missing cap, evidence of flooding or ground movement). contamination of drilled wells usually occurs by surface water entering through the top of the well casing.
- Ensure that the area around the well is kept clear of debris, brush and any potential contaminants (chemical storage, pets, livestock, etc.)
- Ensure the ground surface slopes away from your well
- Do not use or store chemicals near your water supply
- Maintain your septic system to prevent groundwater contamination (see septicsmart! for more information)
- Properly abandon unused wells not being maintained for future use
- See source protection for more information
- Take 3-4 seasonal bacteriological water samples from your house or cottage.
- Take additional samples if you suspect a problem, the colour, taste or smell of your water has changed, or your well has been flooded.
- Always take a sample from a newly constructed or rehabilitated well, and anytime any work is done on the well or plumbing system
- If you have a treatment system and well, take a raw water sample at the same time you take treated water sample, the results can alert you to problems with your well.
- Assess your well for proper construction and monitor it.
Water treatment systems
Disinfection and removal of chemicals, tastes, and odors
Water treatment systems can be used to address drinking water quality or safety issues and are sometimes used as an added safety measure. If your well is considered secure you may not require treatment. Disinfection systems are designed to destroy pathogens – the bacteria and viruses that can cause illness. Most systems do not remove other substances from the water. Metals, minerals and chemicals can cause disagreeable taste and odors, staining, or leave a hard residue that can be hard on appliances and plumbing. Iron, manganese and calcium are a few examples. Hard water will increase soap and detergent usage and shorten the life of appliances that use water.
For more information on treatment systems see private well water manual (a quick users guide)
Cistern private owner
Public Health Ontario
Private well water manual (a quick users guide)
Water wells - best management practices -an in-depth well owner’s resource (order)
Well water records moecc
Wells on your property - moecc
Well aware your well and how to keep you, your family and your water source safe