Sampling & Testing

The frequency of water quality sampling in the Lake Huron & Elgin Area Primary Water Supply Systems exceeds the minimum requirements in place by the Ontario Ministry of the Environment.  Thousands of samples are taken throughout the year, and tested for various physical, chemical and microbiological parameters.  Some samples are tested by the water treatment plant operators at the in-house laboratory, while others are sent away to an external accredited laboratory for analysis. For more information on water quality, please see our Reports page.

Your local municipality will also undertake sampling and testing within the distribution system. Please contact your local municipality for distribution sample test results.

Please visit the website of your local municipality. Municipalities are required by regulation to post their water quality results online.  The information you are looking for may already be available on their website.  In some cases, the municipality may also offer an in-home test for certain parameters (eg. lead).  Please contact them directly for more information.

If you are not able to obtain the information you are looking for from your local municipality and would still like to pursue testing of the water in your home, we recommend you contact a licensed laboratory.  The Ministry of the Environment and Climate Change maintains a List of Licensed Laboratories on their website.  Laboratories with locations in London include ALS, Maxxam Analytics Inc., and SGS Environmental Services.



Fluoridation is a safe and cost-effective way to prevent tooth decay.  Depending on the water source, some municipalities may have naturally occurring levels of fluoride in their drinking water supply.  Others do not, so they adjust their fluoride levels to prevent tooth decay.

At the Elgin Area Primary Water Supply System, hydrofluosilicic acid (HFS) is the chemical used for fluoridation. The Lake Huron Primary Water Supply System does not fluoridate the treated drinking water, however the City of London adds fluoride to the water at the point of supply from the Lake Huron water system.

Any chemical used in the operation of the drinking water system that comes into contact with drinking water must meet applicable standards set by both the American Water Works Association (AWWA) and the American National Standards Institute (ANSI) safety criteria standard NSF/60: Drinking Water Treatment Chemicals – Health Effects.  NSF is responsible for the certification of water treatment chemicals to ensure that they do not contribute contaminants to drinking water that could cause adverse health effects.

Ontario Regulation 169/03 (Ontario Drinking Water Quality Standards) under the Safe Drinking Water Act, 2002, establishes a maximum acceptable concentration of 1.50 mg/L for fluoride in drinking water.  It is further recommended that where fluoride is added to drinking water, the concentration should be adjusted to between 0.60 mg/L – 0.80 mg/L, which is the optimum level for the control of tooth decay.

The target fluoride concentration of the treated drinking water from the Elgin Area Primary Water Supply System is 0.70 mg/L.

For more information, please visit the websites of the following professional organizations:

Middlesex-London Health Unit (MLHU)

Elgin St. Thomas Public Health

Ontario Ministry of Health and Long-Term Care

Canadian Dental Association (CDA)

Health Canada

Canadian Public Health Association (CPHA)

Government of Ontario e-Laws

U.S. Centers for Disease Control and Prevention (CDC)

American Dental Association (ADA)

American Water Works Association (AWWA)

Pharmaceuticals and Personal Care Products in Drinking Water

PPCPs are any products that are used for health or cosmetic reasons, including:

  • Prescription drugs;
  • Over-the-counter drugs;
  • Vitamins;
  • Cosmetics;
  • Lotions and sunscreens;
  • Fragrances;
  • Insect repellent;
  • Common chemicals, like household cleaners.

  • Through the use of personal care products (cosmetics, lotions and fragrances);
  • Activities such as bathing, shaving and swimming;
  • Unused or expired medication being flushed down the toilet or placed in the garbage;
  • Medication residues passing through the body (metabolic excretion);
  • Veterinary medicine;
  • Residues from manufacturing;
  • Hospital residue.

PPCPs have probably been present in drinking water sources for a long time.  Advances in analytical chemistry and technology have enabled laboratories to detect more substances, and at lower levels (trace amounts).  Sophisticated laboratory equipment can now measure chemicals in nanograms per litre (parts per trillion).  To put this into perspective, this concentration is the equivalent of about 1 tsp in 1000 Olympic-size swimming pools.

Pharmaceuticals and personal care products are not regulated in Ontario drinking water.  There is currently not enough scientific data on the potential health effects of PPCPs at minute levels.  Monitoring and research on health effects and the pathways in which PPCPs enter the environment is currently ongoing.

  • Take prescription medication as directed by your doctor or pharmacist;
  • Properly dispose of any unused or unwanted medication;
  • DO NOT flush unwanted medication down the toilet;
  • Many pharmacies offer take-back programs for unused or unwanted medication;
  • Ontario residents have a free, safe and easy way to dispose of pharmaceuticals and household hazardous waste.  Find your local drop-off location at

For more information, please visit the websites of the following professional organizations:

Stewardship Ontario

Ontario residents have a free, safe and easy way to dispose of pharmaceuticals and household hazardous waste.  Find your local drop-off location at:

World Health Organization

Environment and Climate Change Canada

Ontario Ministry of the Environment and Climate Change

University of Waterloo

University of Toronto

What’s in your Water

The average hardness (total, as CaCO3) of the treated water from the Lake Huron Primary Water Supply System is 101 mg/L.

The average hardness (total, as CaCO3) of the treated water from the Elgin Area Primary Water Supply System is 126 mg/L.

Water Hardness Table

Source:  World Health Organization, Hardness in Drinking-water

Some homeowners periodically find a pinkish substance on their bathroom fixtures.  Pink residue is not typically a water quality problem, rather it is due to naturally occurring airborne bacteria.  The bacteria produces a pinkish film or residue on surfaces that are regularly moist, such as toilet bowls, showerheads, sink drains, the bottom of the shower or tub, and tiles.  The pink staining is likely from the bacteria Serratia marcescens.  These bacteria will thrive on moisture, dust and phosphates.  They are naturally occurring in the environment and once airborne, they seek a moist place to grow.  They are often found during and after new construction or remodeling activities, as the dirt and dust stirred up probably contain the bacteria.

The amount of bacteria can be affected by a homeowner’s cleaning habits.  The best solution to keep bathroom fixtures free from this bacterial film is continual cleaning.  A chlorine bleach solution is best.  Periodically add a small amount (three to five tablespoons) of bleach to toilet bowls.  Cleaning and flushing with bleach will not necessarily eliminate the problem, but will help to control the bacteria.  Also try keeping bathtubs and sinks wiped down and dry to avoid this problem.

Yes. Many studies have shown that the amount of chlorine found in municipal drinking water is safe to drink, although some people object to the taste. Chlorine is added to drinking water to kill pathogens (disease causing micro organisms such as germs, bacteria and viruses) and prevent pathogen contamination in the water distribution system.

To eliminate the taste of chlorine, try storing a closed glass pitcher of tap water in the refrigerator. Although some plastic bottles are okay for storing drinking water in the refrigerator, some types of plastic may cause a taste in water. If you are having trouble, use a different kind of plastic.

Bottled Water and Other Water Sources

You don’t need to buy bottled water for health reasons as the drinking water supplied by the Lake Huron and Elgin Area water systems meets all the provincial requirements and standards for drinking water.  If you wish to drink water with a different taste, you can buy bottled water but it may cost as much as 1,000 times more than your municipal drinking water.

Bottled water is considered a “food product” and governed by different regulations and standards than that of municipal drinking water. The content of some minerals and other impurities in bottled water may be listed on the bottle label along with its source. Not all bottled water is “spring water” and, in fact, may be municipal drinking water filtered to remove the chlorine.

No. A typical vinyl garden hose has substances in it to keep the hose flexible. These chemicals, which can get into the water as it goes through the hose, are not good for you or pets.  Do not  fill drinking containers from the garden hose unless the water is allowed to run for a while to flush the hose before using the water.

You can obtain “food-grade” plastic hose which will not contaminate the water. Campers with recreational vehicles or trailers should use this type of hose when hooking up to a drinking water tap at a campsite. Check with a store that sells accessories for recreational vehicles.

Your Water Service

The Lake Huron and Elgin Area Water Systems are responsible for the treatment and supply of drinking water to your local municipality. Each municipality is then responsible for water distribution. Please contact your local municipality for questions relating to your water service and billing.