PFAS in Drinking Water by State: Where Contamination Is Worst

Last updated: May 2026

By PFAS Exposure Claims Resource Center Published: April 2026 8 min read

PFAS contamination in public drinking water is not a regional problem — it is a national one. EPA data collected under the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) found PFAS in thousands of public water systems across all 50 states. But some states, and some communities within them, face dramatically higher contamination levels than others. Here is what the data shows and how to check your own water system.

The New EPA PFAS Standard

In April 2024, the EPA finalized the first-ever federal maximum contaminant levels (MCLs) for PFAS in drinking water. The rule sets enforceable limits for six PFAS compounds:

• PFOA: 4 parts per trillion (ppt)
• PFOS: 4 parts per trillion (ppt)
• PFNA: 10 parts per trillion (ppt)
• PFHxS: 10 parts per trillion (ppt)
• HFPO-DA (GenX): 10 parts per trillion (ppt)
• PFBS (in mixtures): Hazard index standard

These limits are extraordinarily low by historical water quality standards — reflecting the scientific consensus that PFAS are harmful even at very small concentrations. Water systems have until 2027 to come into compliance. Many systems currently exceed these limits and are under obligation to install treatment infrastructure or find alternative water sources.

States With the Highest PFAS Contamination

UCMR 5 data and prior state-level monitoring programs reveal consistent patterns of contamination. States with the most significant documented PFAS drinking water problems include:

Michigan

Michigan has some of the most extensive PFAS contamination in the country, driven by decades of industrial PFAS use at facilities across the lower peninsula. The state identified over 11,000 sites with potential PFAS contamination through its statewide environmental response program. Contaminated communities include areas near PFAS manufacturing plants in Plainfield Township, sites near military installations, and communities in the Grand Rapids area. Michigan has its own state-level PFAS standards, which in some cases are stricter than the new federal limits.

New Jersey

New Jersey has documented PFAS contamination in numerous public water systems, particularly in communities near former industrial facilities in the northern and central parts of the state. The state adopted some of the strictest PFAS drinking water standards in the country before the federal rule. DuPont operations at the Pompton Lakes and Parlin sites have been particularly significant contamination sources.

Pennsylvania

Pennsylvania's contamination is concentrated near military installations — particularly Naval Air Station Willow Grove, Horsham Air Guard Station, and other Philadelphia-area bases that used AFFF firefighting foam containing PFOS and PFOA for decades. Communities in Montgomery, Bucks, and Berks counties have documented contamination in both public water systems and private wells. Residents in these areas have been among the most active plaintiffs in PFAS personal injury litigation.

North Carolina

The Cape Fear River basin in North Carolina became one of the most publicized PFAS contamination cases in the country after the GenX chemical — a PFAS compound used by Chemours (a DuPont spinoff) at its Fayetteville Works plant — was discovered in the drinking water of communities downstream. The litigation spawned by this contamination led to significant settlements and regulatory action against Chemours.

California

California has documented PFAS contamination at hundreds of sites statewide, concentrated around military bases (March Air Reserve Base, Travis Air Force Base, Vandenberg Space Force Base), fire training facilities, and industrial sites. The state's large population means the absolute number of people potentially affected is among the highest in the country.

Ohio

Ohio's contamination is linked to the DuPont Washington Works plant just across the West Virginia border, which contaminated the Ohio River and communities along its banks. Additionally, military installations across the state have documented AFFF contamination. Ohio is the site of the Suboxone MDL but also has active PFAS personal injury litigation.

New York

Long Island has documented PFAS contamination in numerous private wells and some public water systems. Military installations at Gabreski Airport and the former Mitchel Air Force Base are among the identified sources. The state health department has conducted extensive monitoring and provided bottled water to affected households.

Washington State

Washington has contamination linked to military bases including Fairchild Air Force Base and Naval Air Station Whidbey Island, as well as several industrial sites in western Washington. The state was among the early adopters of PFAS-specific legislation.

How to Check Your Water System

You can look up your specific public water system's PFAS test results through several sources:

EPA UCMR 5 Data

The EPA's UCMR 5 database contains PFAS monitoring results for public water systems required to test under the fifth Unregulated Contaminant Monitoring Rule. Systems serving more than 3,300 people were required to test; results are publicly available at EPA.gov. Search by state or water system name to find results for your utility.

Your Annual Water Quality Report (CCR)

Every public water utility is required to provide customers with an annual Consumer Confidence Report (CCR) showing what was detected in the water. Starting with the 2025 reports, PFAS must be included for systems that tested positive. Request your most recent CCR from your water utility or find it on their website.

Environmental Working Group (EWG) Tap Water Database

The EWG maintains a searchable database of water system contaminant data, including PFAS, that is more consumer-friendly than the raw EPA data. Search by zip code at EWG.org to see what has been detected in your water and how those levels compare to health guidelines.

State Environmental Agency Websites

Many states maintain their own PFAS contamination databases and mapping tools. State-level data often includes contamination at sites not covered by federal monitoring requirements, including private wells in areas near known contamination sources.

Private Wells: A Separate Risk

Private wells are not regulated by the EPA's new MCL rule — only public water systems are covered. If you are on a private well in an area near a military base, industrial facility, or other known PFAS source, you should have your water tested independently. Many state health departments offer guidance or subsidized testing for private well owners in PFAS-affected areas.

What If You've Been Drinking Contaminated Water for Years?

If your water system has documented PFAS contamination, or if you live near a known contamination source, consider: getting a PFAS blood serum test to assess your body burden; discussing appropriate health screening with your doctor (kidney function, thyroid, cholesterol); and consulting a PFAS attorney if you have or develop a qualifying health condition.