PFAS in US Drinking Water: A State-by-State Contamination Guide

PFAS Is a National Problem — With Local Variations

EPA UCMR 5 data — the most comprehensive national PFAS testing program ever conducted — paints a stark picture: PFAS has been detected in 100% of the public water systems tested, spanning over 14,000 ZIP codes and more than 6,150 water systems nationwide. But contamination levels, the types of compounds found, and the percentage of systems above legal limits vary significantly from state to state.

Understanding where your state falls — and why — can help you assess your personal risk and make informed decisions about water filtration. This guide covers the national picture, the factors that drive state-level variation, and how to look up results for your specific area.

The National Baseline: What UCMR 5 Found

Before looking at individual states, here is the national summary from EPA UCMR 5 (2023–2025 data, released January 2026):

Metric	National Total
Water systems tested	6,151
Systems with any PFAS detection	6,151 (100%)
Systems above at least one MCL	1,717 (27.9%)
ZIP codes covered	14,090+

The 27.9% figure — more than one in four water systems tested — is higher than many public health officials anticipated when UCMR 5 was designed. Every state in the continental United States has at least some systems with PFAS detections.

What Drives State-Level Differences?

Not all states have equal contamination problems. Several factors determine how heavily PFAS affects any given region:

Industrial Manufacturing History

States with long histories of fluoropolymer and chemical manufacturing tend to have higher PFAS concentrations in water near industrial sites. This includes:

• Ohio, West Virginia, and the Ohio River Valley — DuPont’s Washington Works plant (the source of the landmark C8 litigation) and other chemical facilities
• Alabama — 3M and Solutia manufacturing near Decatur, with documented contamination of the Tennessee River
• New Jersey — Dense industrial base with multiple PFAS-related Superfund sites

Military Installations

States with large numbers of military airfields and fire training areas tend to have significant PFAS plumes from aqueous film-forming foam (AFFF). As described in our military bases article, over 700 installations nationwide have documented contamination.

States with heavy military presence — Colorado, North Carolina, Virginia, Florida, California — frequently show elevated PFAS in communities surrounding bases.

Agricultural Land Application of Biosolids

Treated sewage sludge (biosolids) has been applied to farmland across the country as fertilizer. Biosolids can contain high concentrations of PFAS from industrial and consumer sources that enter wastewater. States with intensive agriculture and widespread biosolid application — including parts of the Midwest and Southeast — can have PFAS in both groundwater and surface water from this source.

Source Water Type

States that rely heavily on groundwater (wells) for public water supplies tend to see higher and more persistent PFAS contamination than those drawing from large surface water bodies. Groundwater moves slowly and retains PFAS for decades; surface water is more dilute and variable.

State Regulatory Environment

Some states have adopted PFAS drinking water standards that go beyond the federal MCLs, requiring utilities to test more frequently and at lower detection thresholds:

• Michigan has some of the most aggressive state PFAS standards, requiring monitoring of 7 PFAS compounds below the federal MCLs
• Massachusetts and New Jersey have state MCLs for certain PFAS that are stricter than the federal rule
• Vermont and Maine have taken early action on PFAS in both water and products

These stricter state standards mean that state data sometimes shows more “violations” than federal data — not because contamination is worse, but because the bar is set higher.

Check Your State

Rather than rank states by contamination levels — which can shift as more data is collected and can be misleading without full context — we have built state-specific pages that show the actual UCMR 5 data for every public water system.

Browse all state contamination pages →

On each state page, you can see:

• Total number of systems tested and the percentage with PFAS above MCL limits
• The most commonly detected compounds in that state
• Individual water systems with their risk level
• Direct links to ZIP code pages for detailed community-level results

Why Absence of Data Isn’t the Same as Absence of PFAS

UCMR 5 required testing of all public water systems serving more than 3,300 people, plus a representative sample of smaller systems. Systems serving fewer people may not have been required to test. Additionally, private well users — approximately 43 million Americans — are entirely outside the UCMR 5 program.

This means:

• Rural areas with many small systems may be underrepresented in the data
• Private well users need to arrange their own testing through a certified lab
• Absence of results in our database for a particular ZIP code doesn’t confirm safe water — it may simply mean that system was not required to test

What to Do With This Information

Knowing your state’s overall picture is a starting point. But PFAS contamination is highly local — a utility a few miles away can have dramatically different results than yours.

The most useful thing you can do:

1. Look up your specific ZIP code — Our free tool shows the actual UCMR 5 results for the water systems serving your area, with compound-by-compound concentration data and comparison to EPA limits.

2. Check your state page — Browse by state to see the full picture for your region, including which systems exceeded MCL limits.

3. If PFAS is detected, consider filtration — Our guide to PFAS removal methods explains which filter technologies work and which don’t, with cost comparisons at every risk level. Our filter reviews cover 12 certified products.

4. If you’re on a private well — Contact your state environmental agency about PFAS testing programs. Many states now offer subsidized or free testing for private well users, particularly near military bases and industrial sites.

5. If your results are above MCL limits — Read our EPA regulations article to understand what your water utility is required to do and by when — and why waiting until 2029 may not be the safest approach for your family.

PFAS contamination in US drinking water is a national problem that requires both federal action and individual awareness. Checking your water is free and takes less than 10 seconds. Start here →