Per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” are persistent synthetic compounds used in a variety of products, including firefighting foams, non-stick cookware, and water-resistant textiles. In Canada, PFAS contamination of drinking water is often linked to the historical use of firefighting foams during training exercises at airports and military bases. These activities have resulted in PFAS migrating into groundwater and affecting private residential wells.
Exposure to PFAS in drinking water has been associated with health risks such as immune suppression, thyroid disruption, and an increased risk of certain cancers. As a result, there has been a significant rise in class actions alleging property value diminution due to the stigma of PFAS-contaminated drinking water. Real estate professionals should be aware of this emerging issue.
Although PFAS contamination is a national concern, this discussion focuses on its specific implications for real estate professionals and property owners in Ontario.
Regulatory Guidelines
Although not legally binding, PFAS drinking water guidelines are influential in contamination-related litigation and due diligence:
- Health Canada has established an interim Objective for drinking water, recommending a group-based threshold of 30 ng/L for the combined concentration of 25 PFAS compounds. This is a precautionary measure, not yet based on a full scientific review or health-based criteria, and there is no current consensus on the most sensitive health effects, and
- Ontario’s Ministry of the Environment, Conservation and Parks (MECP) recommends that the combined concentration of 11 PFAS compounds should not exceed 70 ng/L. This measure is similarly not reliant on health-based criteria.
These guidelines serve as important benchmarks for buyers and sellers. As awareness grows and guidelines become more stringent, buyers may increasingly request PFAS sampling alongside standard well water testing.
Real estate professionals should consider how these benchmarks and the stigma of confirmed or potential PFAS drinking water contamination may influence real estate transactions.
Public Awareness and the Impact of PFAS Drinking Water Contamination Stigma on Residential Property Value
The stigma associated with PFAS contamination can significantly reduce residential property value, even when detected levels are below established drinking water guidelines.
Buyers may avoid properties affected (or potentially affected) by PFAS contamination, seek price reductions, include water-quality conditions related to PFAS in their offers, or require additional testing as a condition of sale. Similarly, lenders and insurers may be reluctant to provide financing or insurance for these properties, potentially affecting their marketability and value.
Canadian courts recognize contamination stigma and its impact on property value as a valid form of compensable damage. Damages in litigation often include compensation for loss of property value, remediation costs, professional fees, and lost financing opportunities. In severe cases, a total loss of marketability may even be claimed. Importantly, PFAS risk does not have to be proven hazardous to affect market value; mere suspicion or public perception alone can impact a property’s desirability and value.
Rising Public Awareness and Mapping of PFAS Contamination Hotspots
Public perception of PFAS contamination is being influenced by national reports and news coverage. The Health Canada and Environment and Climate Change Canada 2025 Final State of PFAS Report confirms the presence of PFAS contamination at over 100 federal sites and identifies their specific locations on a Hotspot Map. This Report also recommends designating most PFAS as “toxic” under Part 2 of Schedule 1 of the Canadian Environmental Protection Act.
The Report identifies certain locations—particularly sites where PFAS has been used, such as firefighting training areas—as “hot spots” with potentially elevated PFAS levels (see Figure 1). Because PFAS is highly mobile, it can travel several kilometers through groundwater and surface water, greatly increasing the area affected by a single contamination source. The Report highlights that a primary pathway for human exposure is the consumption of drinking water contaminated by PFAS migrating from these impacted sites.
News outlets such as the CBC and The Globe and Mail have similarly published interactive PFAS hotspot maps, further raising public awareness, particularly for areas near military bases and airports nationwide. This reporting provides additional insight through an interactive map pinpointing exactly where these PFAS “hotspots” are located, especially in relation to communities that rely on private groundwater wells for their drinking water across Canada.
In Ontario, notable hotspots include but are not limited to (see Figure 2):
- Canadian Forces Base (CFB) Trenton, Quinte West
- Canadian Forces Detachment Mountain View, Prince Edward County
- CFB North Bay and the Jack Garland Airport, North Bay
- Hamilton International Airport
- London International Airport, and
- National Research Council of Canada National Fire Laboratory in Mississippi Mills.
As public awareness of PFAS and related regulatory developments increases, it is important for real estate professionals to remain appraised of potential areas of concern. Real estate professionals may wish to proactively monitor these developments and consider advising clients accordingly.
PFAS Class Actions
Class action litigation related to PFAS contamination migrating from federal facilities is expanding across Canada.
In Ontario, a certified class action is already underway, while similar uncertified cases are proceeding in Newfoundland and Labrador and Nova Scotia. These lawsuits demonstrate that PFAS contamination has become not only a scientific and environmental issue but also a significant concern for property transactions and litigation.
In Ontario, the Mann Lawyers Environmental Law Group is litigating class actions involving sites such as Mississippi Mills (Egan et al. v. National Research Council of Canada) and CFB North Bay and the Jack Garland Airport in North Bay (Sway and Currie v. The Attorney General of Canada and the Corporation of the City of North Bay). These class actions seek damages on behalf of hundreds of homeowners who allege that the migration of PFAS from federally operated facilities has diminished their property values due to the resulting stigma associated with their PFAS-contaminated groundwater wells.
Real Estate Professional Responsibilities
Real estate professionals have a legal duty to disclose known material latent defects, which could potentially include environmental issues like PFAS contamination. In light of the above mentioned PFAS contamination hotspot maps, key potential due diligence questions for real estate professionals to consider may include:
- Is the property near a known PFAS hotspot?
- Does the property rely on a private well or municipal water?
- Are there nearby potential sources of PFAS, such as airports or military bases?
- Has the water been tested for PFAS, or has the owner received any related communication about contamination?
If a seller conceals a known PFAS risk and the buyer later discovers it, both the seller and the agent could face legal liability. The Real Estate Council of Ontario requires agents to disclose any fact the seller is legally obligated to disclose and to obtain written acknowledgment from buyers who receive such disclosures.
In light of this, real estate professionals may consider recommending PFAS testing if contamination is suspected and ensure all relevant information is transparently shared with potential buyers.
Conclusion
PFAS contamination is an emerging market factor that can influence property values, disclosure obligations, and financing options, particularly where PFAS contamination in groundwater drinking wells is confirmed.
As regulatory guidelines and public awareness continue to evolve, real estate professionals should stay informed about Health Canada and MECP recommendations, PFAS hotspot maps, and related class actions involving property value diminution.
Proactive due diligence, clear communication, and a strong understanding of PFAS-related issues are essential for managing risk and supporting clients in today’s evolving PFAS contamination regulatory, litigation and real estate landscape.
This blog post was written by Michael Hebert member of the Mann Lawyers Environmental Law team and Nathan Adams (primary author), member of the Mann Lawyers Business Law team and Environmental Law team. Michael can be reached at 613-369-0360 or at michael.hebert@mannlawyers.com and Nathan at 613-369-0380 or at nathan.adams@mannlawyers.com.
