Ontario does not regulate or mandate routine testing for per- and polyfluoroalkyl substances (PFAS), also referred to as “forever chemicals”, in its drinking water regulations.
PFAS are not listed in the Ontario Drinking Water Quality Standards under the Safe Drinking Water Act, 2002 which lists the legal limits allowed in drinking water of 151 microbiological, chemical, and radiological parameters like lead and mercury.
In 2024, Canada introduced the Drinking Water Objective of 30 ng/L (nanograms per liter) for 25 different PFAS. As of 2024, the Ontario’s Ministry of the Environment, Conservation and Parks (MECP) is reviewing the basis of Health Canada’s new objective and will assess the applicability for its use in Ontario and the best way to implement it.
PFAS are used in many industrial and consumer products such as adhesives, cosmetics and cleaning products. They’re also used in specialized chemical applications, such as fire-fighting foams, and in water-, stain- and oil-repellent coatings for fabrics and paper.
The current data we have on PFAS in Canadian freshwater sources and drinking water are limited. The data we do have suggest that PFAS are present across Canada at levels generally below the objective. The concentrations of PFAS in freshwater and drinking water may be higher near:
Health Canada
- facilities that use large amounts of these chemicals
- locations where fire-fighting foams containing PFAS were used to put out a fire
- landfills and wastewater treatment plants
Studies link exposure to PFAS to health issues
PFAS are a group of anywhere from 15,000 up to over 7 million man-made chemical compounds and not all of which can be detected by current testing methods, making them difficult to study.
Many PFAS such as PFOS and PFOA pose health and environmental concerns because they are persistent organic pollutants with extremely persistent properties and resistance to degradation, leading to them being branded as “forever chemicals” in an article in The Washington Post in 2018.
The research conducted to date reveals possible links between human exposures to certain PFAS and some adverse health outcomes. These health effects include cancer, liver damage, immune system disruption, and developmental issues.
Health information exists for only a small number of PFAS. What we do know is that some PFAS may affect many systems and organs, such as:
- the liver, kidney and thyroid
- the immune and nervous systems
- development and the reproductive system
- metabolism and bodyweight
The potential health risks from exposure depend on how much and how many of the PFAS you are exposed to and for how long. Each person’s specific attributes including their age, habits, and overall health can impact how their body will react to chemical exposures.
Health Canada
After thoroughly reviewing the extensive published literature, the Working Group classified PFOA as carcinogenic to humans (Group 1) and PFOS as possibly carcinogenic to humans (Group 2B).
International Agency for Research on Cancer (IARC)
Current peer-reviewed scientific studies have shown that exposure to certain levels of PFAS may lead to:
US EPA
- Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women.
- Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations, or behavioral changes.
- Increased risk of some cancers, including prostate, kidney, and testicular cancers.
- Reduced ability of the body’s immune system to fight infections, including reduced vaccine response.
- Interference with the body’s natural hormones.
- Increased cholesterol levels and/or risk of obesity.
health effects include:
US National Institute of Environmental Health Sciences
- Altered metabolism and body weight regulation, and risk of childhood obesity.
- Increased risk of some cancers.
- Reduced ability of the immune system to fight infections.
- Folate may reduce PFAS accumulation in the body, which may protect against adverse birth outcomes and boost immune health.
- A high-fiber diet may decrease metabolic disease risks associated with exposure to PFOS, a type of PFAS. Although PFOS use has been phased out, it can still be found in drinking water, groundwater, soil, and air.
- Exposure to certain PFAS may be associated with increased risk of thyroid cancer.
- A large-scale study on exposure to PFAS in humans and rodents showed consistent evidence of liver damage.
- A long-term study showed a link between PFAS exposure and increased risk of Type 2 diabetes in women.
- Exposure to PFAS in adolescents was linked to a decrease in bone mineral density over time.
PFAS producers have paid billions of dollars to settle litigation claims. 3M and DuPont knowingly concealed the serious health risks of so-called ‘forever chemicals’ in their products for decades.
In 2023, 3M agreed to pay at least $10.3B to settle lawsuits relating to PFAS contamination in US public drinking water systems while Dupont agreed to pay $1.2B. Dupont agreed to another $27M payout as recently as July 2025 relating to water contamination.
Due to its common use in everyday products, almost everyone is exposed to low levels of PFOS and PFOA from the air, soil, indoor dust, food, drinking water, and various consumer products.
PFAS compounds are highly mobile, bioaccumulating in fish and wildlife and can be absorbed through human skin and through tear ducts, and products on lips are often unwittingly ingested.
Canada has prohibited the manufacture, use and sale of PFAS and PFOA since 2012 and set drinking water guidelines for PFAS
Canada enforces the Prohibition of Certain Toxic Substances Regulations, 2012 (PCTSR), which bans the manufacture, use, sale, offer for sale, and import of PFOS, PFOA, long-chain PFCAs (LC-PFCAs), their precursors, and products containing them. Limited exemptions apply, such as for aqueous film-forming foam (AFFF) containing PFOS at concentrations up to 10 ppm.
Historically, PFOA and PFOS were imported into Canada but not manufactured. Canada imported approximately 600 tonnes of perfluorinated alkyl compounds between 1997 and 2004, of which 43% were PFOS and their precursors. This includes AFFF containing PFOS used by firefighters and military and civil aviation industries. It is estimated that approximately 300 tonnes of this AFFF stockpile (which contains about 3 tonnes of PFOS) of which 10% is used annually.
Carex Canada
- In 2017, Ontario developed interim advice recommending that drinking water used for human consumption not exceed 70 ng/L for 11 different PFAS, but this was only applied and tested for where PFAS had been detected in water.
- In 2018, the Government of Canada provided the Guidelines for Canadian Drinking Water Quality for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA).
- August 9, 2024, the Government of Canada withdrew those guidelines and introduced the Drinking Water Objective of 30 ng/L (nanograms per liter) for 25 different PFAS. Canada does not yet have federal PFAS limits. For comparison, the EU’s recast Drinking Water Directive (DWD) (EU) 2020/2184 limits total PFAS in drinking water to 0.5 µg/L (500 ng/L) and levels for 20 individual PFAS to 0.1 µg/L.
As of 2024, Ontario’s Ministry of the Environment, Conservation and Parks is reviewing the basis of Health Canada’s new objective and will assess the applicability for its use in Ontario and the best way to implement it.
The Government of Canada’s “State of PFAS” expects releases to occur during the manufacture, processing, use, and disposal of PFAS-containing products such as electronics (wires, coatings), textiles, rubber, coated silicone, tickers, moulded plastics, personal care products and more.
Potential PFAS-handling facilities are not required to report their PFAS releases to the National Pollution Release Inventory (NPRI) and product importers and retailers are not required to disclose PFAS content to regulators or consumers.
Limits for PFAS in drinking water in other countries
Other places such as the European Union (EU), Sweden, Denmark and some states in the United States (US) have also established single guideline limits for PFAS in drinking water. For example, the EU has limits of 100 ng/L for the sum of 20 PFAS and 500 ng/L for the sum of all PFAS in drinking water. The US Environmental Protection Agency has established individual maximum contaminant levels (MCLs) of 4 ng/L for each of PFOS and PFOA.
Health Canada
PFAS in drinking water may be higher near landfills, airports, military bases and wastewater treatment plants
Residues are now commonly found in rain, drinking water, and wastewater.
The concentrations of PFAS in freshwater and drinking water may be higher near:
Health Canada
- facilities that use large amounts of these chemicals (eg. airports, military bases)
- locations where fire-fighting foams containing PFAS were used to put out a fire
- landfills and wastewater treatment plants
Canada’s Federal Contaminated Sites Inventory identifies sites under federal custodianship or that the Government of Canada has accepted some financial responsibility for, that are known or suspected to be contaminated with PFAS, including fire training sites and sites at which Per- and Polyfluoroalkyl Substances (PFAS) are a concern. CBC has a map of PFAS Hotspots using this data.
It does not include sites where contamination has been caused by, and which are under the control of, enterprise Crown corporations, private individuals, firms or other levels of government.
Drinking Water Surveillance Program received PFAS data from 23 out of 444 municipalities
Municipal monitoring of PFAS in drinking water is voluntary so there is limited available data for municipal drinking water systems in Canada.
Ontario’s Drinking Water Surveillance Program (DWSP) was a voluntary program that municipalities could participate in that monitored and reported on drinking water quality at for scientific and research purposes from ran from 1998 to 2020. PFAS participating municipalities tested for included:
- PFOS – Perfluorooctane sulfonate
- PFOA – Perfluorooctanoic acid
- PFHxS – Perfluorohexanesulfonic acid
- PFNA – Perfluorononanoic acid
- HFPO-DA -Hexafluoropropylene oxide dimer acid
- PFBA – Perfluorobutanoic acid
- PFPeA – Perfluoropentanoic acid
- PFHxA – Perfluorohexanoic acid
23 drinking water systems tested in Ontario were below Canadian guidelines
Monitoring results since 2016 for 23 drinking water systems participating in the ministry’s voluntary Drinking Water Surveillance program show that levels in Ontario are generally below the Health Canada Objective. Some systems may have temporarily exceeded the Objective due to transient events (for example, nearby firefighting activities). The North Bay Drinking Water System is the only known system in Ontario that consistently exceeds the Objective due to historic PFAS contamination.
Minister’s Annual Report on Drinking Water (2024)
Peel Region participated in PFAS studies led by the MECP from 2016 to 2019.
Fourteen (14) PFAS compounds were tested in twenty-five (25) drinking water systems in Ontario and the highest average PFAS compound detected in these drinking water systems was 2.4 ng/L. Additional PFAS testing by the MECP on 635 drinking water samples collected from thirteen (13) drinking water systems in Ontario did not detect concentrations above 10 ng/L in any sample.
Report on “Forever Chemicals” and Peel Region Drinking Water – Peel Region (2024)
Here are the Drinking Water Systems that tested for Perfluorindated Alkyl Compounds (PFCs) – now called PFAS:
- Asubpeeschoseewagong First Nations
- Bare Point Road (Thunder Bay) 2013-2014
- Bayside (Quinte West) 2012-2018
- Brockville 2013, 2015-2016
- Brantford 2012-2016, 2018-2020
- Toronto 2012, 2014-2016, 2018-2019
- Cornwall 2015-2016
- Decew Falls-Niagara Falls (Niagara-on-the-Lake) 2015-2017
- Dunnville (Haldimand County) 2012-2016
- Glen Walter (South Glengarry) 2012-2016
- Goderich 2012-2018
- Guelph 2012-2015
- Hamilton 2012-2016
- Hawkesbury 2012-2018
- Kenora Area 2012-2020
- Ohshweken 2012-2016
- Orangeville 2015-2018
- Prescott 2015-2017
- Sault Ste. Marie 2013-2014
- Smiths Falls 2012-2014
- South Peel 2012-2016
- Terrace Bay 2012-2015
- Lakeshore 2012-2018
- Trenton 2012-2018
- Valley (Greater Sudbury) 2012-2018
- Windsor 2019-2020
All tests found 10 ng/L or less of each PCF tested for, except for:
- Brantford (10, 13, 15 in 2016)
- Kenora Area (13 in 2016)
The full dataset can be found on Open Government Canada.
Municipalities that test for PFAS
Peel Region
Peel Region participated the Drinking Water Surveillance Program led by the MECP from 2016 to 2019 and has been voluntarily testing for PFAS since 2020. Since November 2022, staff have been testing both source water and treated drinking water semi-annually at Peel Region municipal wells and water treatment plants.
Peel Region’s June 27, 2024 report found that the PFAS levels detected through Peel’s water testing program are below Health Canada’s proposed total PFAS limit and the new US Environmental Protection Agency’s (USEPA) limits for the parameters Peel tests.
North Bay
Forever chemicals from firefighting training exercises at the airport decades ago have seeped into Trout Lake, the source of the city’s drinking water.
National Defence tested wells at 162 properties since 2023; 66 of those had levels above 30 ng/L. From 2017 to 2022, MECP tested PFAS in drinking water quarterly. The average of the quarterly results for North Bay for those five years was 58.1 ng/L.
Department of National Defence covered most of the $20M bill to remove and treat contaminated soil from the airport and the city is now exploring options to upgrade its water treatment plant to treat the PFAS that remains.
If you live within the surroundings of the Jack Garland Airport or CFB 22 Wing, contact DND at 705-494-2011 to see if you qualify to be included into their testing program. You will be provided with all the necessary information about the process if you qualify.
If you are outside of this area, you do not qualify to enter DND program. PFAS testing requires a stringent and complex sampling procedure. Owners who would like to test their own water should contact a licensed private environmental laboratory to discuss collection, shipment, and the related cost of analysis. Failing to follow sampling procedure may influence sample accuracy. The Ontario Public Health Laboratory does not conduct PFAS testing.
North Bay Parry Sound District Health Unit
Torbay, NL residents’ class-action lawsuit against Transport Canada
Montreal
A University of Montreal study published in 2023 analyzed PFAS contamination in tap water from 376 different municipalities in Quebec. More than 99% of the tap water samples were positive for at least one PFAS, which ranged from below detection limits to 108 ng/L. But only about 5% of the total water supply samples had levels above Canada’s new objective value.
Target and nontarget screening of PFAS in drinking water for a large-scale survey of urban and rural communities in Québec, Canada
Municipalities that use Granular Activated Carbon (GAC) filters
GAC is a highly porous adsorbent material made from sources like bituminous coal, processed to maximize surface area and pore structure. It works primarily through adsorption, where contaminants adhere to, and are trapped by, the surface of the carbon particles.
While they are often implemented to remove bad tastes and odours, they are also capable of filtering out some PFAS.
GAC is highly effective at adsorbing PFAS compounds, especially longer-chain ones like PFOS and PFOA.
Some municipalities in Ontario install filters from companies such as Continental Carbon Group in their Drinking Water Systems.
Cost to test for PFAS
A 14 to 40 component scan for PFAS can cost $400 to $500 plus $3 per sample plus tax and have a turnaround time of 2-4 weeks.
Peel states that many Contaminants of Emerging Concern (CECs) such as microplastics cannot be tested by commercial laboratories, or their analysis is cost-prohibitive for municipalities.
PFAS treatment can be cost-prohibitive
The US EPA research recommends the following water treatment options as the most effective in removing PFAS from drinking water:
- Granular activated carbon (GAC) – use carbon to trap chemicals as water passes through them.
- Nanofiltration (NF) – (>90% effective) – forces water through an extremely thin barrier that separates chemicals from the water.
- Reverse osmosis (RO) (>90% effective) – forces water through an extremely thin barrier that separates chemicals from the water. Reverse osmosis membranes are tighter than nanofiltration membrane.
- Anion exchange resins – tiny beads that act like powerful magnets that attract and hold the contaminated materials from passing through the water system.
Currently, there are no regulatory limits on PFAS in drinking water in Ontario, so many water treatment facilities are not intentionally designed to remove them.
Upgrading Peel’s large water treatment facilities to NF filters or reverse osmosis would require a large capital investment.
Studies on the capital cost impact that PFAS may have on water treatment have not been completed to date.
How to reduce your exposure to PFAS in drinking water
Ingesting contaminated drinking water and food is the main route of exposure. Other potential routes include dermal contact with consumer products and inhaling contaminated air and dust.
If you do have PFAS in your drinking water, you can remove them by treating your water with a treatment unit or system. You can install:
- an activated carbon filter directly at the tap or where the water enters the house
- a reverse osmosis system at the tap
- an ion exchange system designed for PFAS removal
Make sure that any unit or system you buy is:
Health Canada
- certified to NSF International standards, NSF/ANSI Standard 53 (activated carbon) or NSF/ANSI Standard 58 (reverse osmosis) for PFAS removal
- these standards ensure the safety and performance of the device
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