PFAS in Drinking Water: What Every Homebuyer Should Know About Forever Chemicals

PFAS — per- and polyfluoroalkyl substances — are a group of about 12,000 synthetic chemicals used since the 1940s to make products heat-resistant, water-resistant, and non-stick. They earned the nickname “forever chemicals” because they don't break down in the environment or in the human body. They accumulate.

EPA estimates that 176 million Americanshave drinking water that has tested positive for PFAS. For anyone buying or renting a home, that number is a reason to ask a specific question about the property's water system — not to panic, but to know what you're walking into.

What PFAS Are (and Why They Matter for Real Estate)

PFAS is an umbrella term. The most studied compounds — PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate) — were phased out by major manufacturers in the early 2000s after EPA raised concerns about their persistence. But they're still widely detected in water because they don't degrade; they just move through soil and groundwater at a slow, steady pace.

Newer PFAS compounds — PFHxS, PFNA, HFPO-DA (a DuPont replacement sold as GenX) — are still in commercial use and are now also showing up in monitoring data.

The health research is ongoing, but EPA has linked PFAS exposure to immune system effects, thyroid disruption, increased cholesterol, and elevated risk for certain cancers at high or prolonged exposures. The key word is “prolonged” — a single exposure is very different from decades of daily drinking water consumption.

The Federal MCL: What 4 ppt Actually Means

In April 2024, EPA finalized the first-ever federal Maximum Contaminant Levels (MCLs) for PFAS in drinking water:

• PFOA: 4 ppt (parts per trillion)
• PFOS: 4 ppt
• PFHxS, PFNA, HFPO-DA: 10 ppt each
• PFBS: 2,000 ppt

Parts per trillion is genuinely tiny. Four ppt is roughly one drop of water in 20 Olympic swimming pools. EPA chose this level not because harm is certain at 4 ppt, but because it is close to the detection limit of modern lab equipment and represents a precautionary limit based on the best available toxicology.

Water utilities have until 2029 to comply. That means right now, some systems are legally serving water above the MCL while they build treatment infrastructure. If a system is above the limit, they are required to notify customers and report it — but they are not yet required to have fixed it.

Where PFAS Contamination Comes From

PFAS contamination in drinking water has three main source categories that are relevant when evaluating a property:

1. Industrial Discharges

Chemical plants, semiconductor manufacturers, metal plating facilities, and some textile mills use or release PFAS. They often discharge into surface water or groundwater near their operations. Properties within a few miles of former or active industrial PFAS users may have elevated groundwater PFAS — relevant if there's a private well on the property.

2. Military Bases and Airports

The Department of Defense used aqueous film-forming foam (AFFF) — a PFAS-containing firefighting chemical — extensively for decades on military airfields. More than 700 military installations have confirmed or suspected PFAS releases. The contamination plumes from these sites can travel through groundwater for miles and reach municipal water supplies and private wells in surrounding communities.

If you're looking at a property within 5–10 miles of a military base, the DoD PFAS installation list is one of the most important checks you can do.

3. Biosolids Land Application

Treated sewage sludge (“biosolids”) is commonly applied to agricultural land as fertilizer. PFAS from household products and industrial sources concentrate in sludge. When biosolids are applied to fields, PFAS can leach into groundwater. This is a significant concern for rural properties with private wells near agricultural land.

UCMR 5: The Dataset Behind the PFAS Screen

EPA's 5th Unregulated Contaminant Monitoring Rule (UCMR 5) required public water systems serving more than 3,300 people to test for 29 PFAS compounds between 2021 and 2024. The results are publicly available in EPA's bulk dataset.

VetMyAddress loads this dataset directly and queries it by the water system ID (PWSID) matched to your address. When you run a report, you get:

• Which PFAS compounds were detected, if any
• Whether any detections exceed the 2024 federal MCL
• The highest detected concentration in parts per trillion
• Which utility's data is being used

Important caveat:UCMR 5 covered larger systems. Smaller systems (under 3,300 people) were not required to test. If your address is served by a small rural system, the PFAS record may be blank — not because the water is clean, but because testing wasn't required.

Private Wells: A Different Problem

If a property has a private well, none of the federal monitoring data applies. Private wells are not regulated by EPA and are not tested under UCMR 5. The only way to know what's in a private well is to test it.

For properties with private wells near military installations, industrial sites, or agricultural land with known biosolid application, PFAS well testing is not optional — it's the only data point you have. A certified laboratory test for a standard PFAS panel costs $150–$400 and takes about two weeks. Get it done before closing.

What Homebuyers Should Actually Do

Step 1: Check the water system type

Is the property on a public water system or a private well? The listing agent or seller disclosure should say. If it's public: proceed to Step 2. If it's a private well: skip to Step 5.

Step 2: Look up the utility's UCMR 5 results

VetMyAddress surfaces this directly from the EPA dataset in your report. You can also search EPA's UCMR Data Finder directly if you want the raw data.

Step 3: Read the Consumer Confidence Report

Every public water system publishes an annual Consumer Confidence Report (CCR) by July 1. Search “[utility name] Consumer Confidence Report 2025” to find it. It lists every contaminant tested and the result. If the utility has PFAS detections, the CCR will describe them and any remediation plans.

Step 4: Ask about treatment plans if PFAS exceeds the MCL

If the report shows exceedances, the utility is required to notify customers and is likely working toward compliance by 2029. Ask for the current treatment plan. Point-of-use reverse osmosis filters certified to NSF/ANSI 58 can reduce PFAS at the tap in the interim.

Step 5: Test private wells before closing

No negotiation, no “we'll check after we move in.” A PFAS panel test is a standard due diligence item for private wells near any of the three source categories listed above. Contact a state-certified lab through your state environmental agency's website.

How VetMyAddress Checks This

When you run an address report, the PFAS section checks three data sources:

• EPA UCMR 5 — drinking water PFAS detections for the matched water utility, queried by the same PWSID used in the Drinking Water section
• EPA TRI (Toxics Release Inventory) — industrial facilities reporting PFAS chemicals within 5 miles of the address
• DoD PFAS Installation List — military installations with known PFAS releases within 5 miles

All three datasets are loaded directly from federal bulk data into our database — not pulled from live APIs at query time — so results are consistent and fast. The data is refreshed when EPA and DoD publish updates, typically quarterly.

The Bottom Line

PFAS is the most significant new category of environmental due diligence for homebuyers in a generation. The data is now public, federal limits are set, and the testing infrastructure exists to check any address in about 30 seconds. There's no reason to buy a home without knowing whether the water system has detections on record.

A detection below 4 ppt is not a deal-breaker. A detection above 4 ppt is something to understand fully — including the utility's remediation timeline — before you close. And a property served by a private well near a military base or industrial site needs a test, full stop.