What is EPA UCMR 5 PFAS data?

UCMR 5 is the U.S. EPA’s fifth Unregulated Contaminant Monitoring Rule — a round of nationwide drinking-water sampling (2023–2025) that measured 29 PFAS compounds plus lithium at the point where water enters each system. These pages summarize the highest detected PFOA and PFOS results for large systems; the figures do not indicate compliance or noncompliance with any standard.

How do I reduce PFAS in my drinking water?

PFAS is an ingestion-route contaminant, so the certified, cost-effective fix is usually a point-of-use reverse-osmosis filter at the kitchen tap. A small number of whole-house units carry a genuine third-party certification for PFOA/PFOS if you want reduction at every tap.

PFAS in U.S. Water Systems, by Location

The EPA's UCMR 5 program sampled drinking water across the country in 2023–2025. Below are 680 large public water systems (each serving more than 10,000 people) where PFOA or PFOS was detected at or above 6 parts per trillion. Pick a state to see the systems, the highest levels detected, and the certified filters that reduce PFAS.

680water systems with detections

47states & territories

2023–25EPA UCMR 5 sampling window

4 pptfederal reference (PFOA/PFOS)

Choose a state

State	Systems with detections	Highest detection (ppt)
Alabama	34	59.4
Alaska	2	9.1
Arizona	13	55.8
California	91	59
Colorado	4	15.8
Connecticut	16	16.2
Delaware	8	25.3
Florida	83	50.3
Georgia	17	56
Guam	1	135
Idaho	1	28.2
Illinois	6	18
Indiana	3	12.9
Iowa	2	7.2
Kansas	2	21.1
Kentucky	8	47.9
Louisiana	2	6.4
Maine	2	7.1
Maryland	5	23.3
Massachusetts	43	92
Michigan	2	10
Minnesota	8	23.7
Mississippi	2	72.2
Montana	1	6.6
Nebraska	3	17
Nevada	2	46
New Hampshire	5	9
New Jersey	82	44
New Mexico	1	7.4
New York	13	19
North Carolina	43	35.6
Northern Mariana Islands	1	32.1
Ohio	20	28.9
Oklahoma	5	51.3
Oregon	4	12
Pennsylvania	33	153
Puerto Rico	9	46.7
Rhode Island	6	16
South Carolina	24	18
Tennessee	18	35
Texas	23	82
Utah	1	7.1
Virginia	8	9.1
Washington	15	52.2
West Virginia	3	179.5
Wisconsin	4	14
Wyoming	1	7

Counts are large public water systems (serving more than 10,000 people) where EPA UCMR 5 monitoring detected PFOA or PFOS at or above 6 ppt. "Highest detection" is the single highest PFOA or PFOS result recorded in that state's included systems — context only, not a compliance or health determination.

What these pages are — and aren't

Each system page states what PFAS were detected and at what highest level, then routes you to the certified products that reduce them. The honest first step for your own water is always a test — how to test your water first — and you can run the selector for a recommendation tailored to your home.