PFAS in Drinking Water Map: Check Your Water by ZIP Code

PFAS, the group of long-lasting industrial compounds often called “forever chemicals,” have turned up in drinking water across the United States. This interactive map shows what the EPA actually measured in nearly 10,300 public water systems during its nationwide 2023 to 2025 testing, and lets you check the systems that serve your ZIP code against the new federal limits.

Type in your ZIP code or address, or tap the locate button, and the map shows the public water systems that serve your area, which PFAS were found in each one, and how those results compare to the 2024 federal limits for PFOA, PFOS and four other PFAS. Every system is color coded: red for a result at or above a limit, amber for PFAS detected below the limits, and green for no PFAS detected.

The data comes straight from the EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), the largest PFAS testing program ever run on American tap water. It is a snapshot of monitoring results, not a pass or fail grade, and it is explained in plain English below the map.

PFAS in Drinking Water Map

How to use it

1. Enter your 5 digit ZIP code and press Check, or type an address, or tap Locate to use your current location.
2. Read the “water systems serving your ZIP” panel. Each card names a public water system, its result, and the PFAS that were detected with their levels in parts per trillion (ppt).
3. Open any system to see its full result: every PFAS detected, the value measured, and the 2024 federal limit for comparison.
4. Explore the national map. Zoom and pan to see every tested system, colored by result, and click a marker for details.
5. Use the filters to focus on one state, one result type, or only the systems at or above a limit, and use Share to copy a link to your view.

About the data

Source. All results come from the EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), a nationwide program in which public water systems tested their water for 29 PFAS and lithium between 2023 and 2025. Large systems and a representative sample of small systems took part. The dataset on this map covers nearly 10,300 systems and is current through the EPA’s data release dated February 2026.

What the results mean. Of the systems tested, about 1,975 detected at least one of the five PFAS that now have a federal limit, and about 1,746 had a PFAS at or above one of those limits in at least one sample. The 2024 federal limits are 4 ppt for PFOA and 4 ppt for PFOS, 10 ppt each for PFHxS, PFNA and GenX (HFPO-DA), and a Hazard Index of 1 for certain mixtures. Levels are shown in parts per trillion, the same units the limits are written in.

An important measurement detail. UCMR 5 could only measure PFOA and PFOS down to 4 ppt, which happens to be the exact level of the new limit. That means any UCMR 5 detection of PFOA or PFOS is at or above the limit, and a result of “not detected” means the level was below 4 ppt, not necessarily zero.

How systems are placed on the map. UCMR 5 does not publish a map location for each system, so each one is shown at the center of the ZIP codes it serves (a state level position is used for a small number of systems whose ZIP codes could not be matched). A water system serves an area, not a single point, so the markers are approximate and do not mark a source of contamination or any specific address. ZIP code centroids come from the free US Census 2024 gazetteer.

Refresh. The EPA adds new UCMR 5 results roughly every quarter and reporting finishes in 2026. This map is rebuilt from the latest EPA file and carries a data date stamp in the footer of the app.

Important: what this map is and is not

This map is for general information only. It is not medical or health advice, and it is not a compliance or enforcement determination. Whether a water system meets the 2024 federal PFAS limits is decided by state regulators using a running annual average over a full monitoring period, and utilities have until the end of the decade to comply, so a single result at or above a limit here does not mean a system is in violation. Because UCMR 5 could only measure PFOA and PFOS down to 4 ppt, “not detected” means below 4 ppt, not zero. Private wells and many very small systems were not part of UCMR 5, so the absence of a nearby result does not mean your water is free of PFAS. To learn what is in your tap water, read your utility’s annual Consumer Confidence Report and contact your water provider or state drinking water program.

Frequently asked questions

Where does this PFAS data come from?

Every result on this map comes from the EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), a public program that required nearly 10,300 public water systems to test their water for 29 PFAS and lithium between 2023 and 2025. It is public domain data published by the EPA.

What are PFAS, or forever chemicals?

PFAS (per- and polyfluoroalkyl substances) are a large family of human made chemicals used since the 1940s in things like nonstick coatings, firefighting foam, and stain and water repellents. They break down very slowly, which is why they are called forever chemicals, and some have been linked to health effects, which is why the EPA set drinking water limits for a handful of them.

What are the new EPA limits for PFOA and PFOS?

In April 2024 the EPA set enforceable drinking water limits of 4 parts per trillion each for PFOA and PFOS, 10 parts per trillion each for PFHxS, PFNA and GenX (HFPO-DA), and a Hazard Index of 1 for certain mixtures of PFHxS, PFNA, GenX and PFBS. Water systems generally have until 2029 to 2031 to meet them.

Does “not detected” mean my water is safe?

Not exactly. UCMR 5 could only measure PFOA and PFOS down to 4 ppt, so “not detected” means the level was below 4 ppt, not necessarily zero. It is a reassuring result, but this map is a snapshot of one testing program and is not a guarantee about your specific tap.

My ZIP code shows no water system. What does that mean?

It means no public water system serving that ZIP code was part of UCMR 5. Private wells and many very small systems were not tested. It does not mean the water is free of PFAS. Your utility’s annual Consumer Confidence Report is the best place to learn what is in your water.

Is a result at or above a limit a violation?

No. UCMR 5 is monitoring data, not a compliance decision. Whether a system meets a limit is decided by state regulators using a running annual average over a full monitoring period, and utilities have years to comply. A single sample at or above a limit here flags a system worth looking into, not a legal violation.

How do I find out what is actually in my tap water?

Every community water system must publish an annual Consumer Confidence Report, also called a water quality report, that lists what it tests for and finds. Contact your water provider or your state drinking water program for the most complete and current information for your address.

How fresh is this data?

This map uses the EPA’s UCMR 5 release dated February 2026, which contains results collected from 2023 through 2025. The EPA adds new results roughly every quarter and finishes reporting in 2026. The app footer shows the exact data date.