For journalists & researchers
Press & data
CheckPFAS is a free, independent tool that maps the EPA's UCMR 5 PFAS testing (2023–2025) to every US ZIP code. Reporters and researchers are welcome to cite the figures below — they're drawn straight from the EPA's public data. Need a custom extract (a specific county, utility, or compound)? Email us.
Figures current as of June 13, 2026 · Source: EPA UCMR 5
01Key statistics
~10k
public water systems tested under EPA UCMR 5
6,151
had PFAS detected (61.5%)
1,717
exceed EPA limits (17.2%)
123×
worst single result, the EPA limit (NASHVILLE, TOWN OF, NC)
14,090
ZIP codes covered, across 51 states & territories
14
states with their own PFAS limits (stricter than or alongside federal)
02Notable findings
Worst single result
NASHVILLE, TOWN OF, NC measured PFOS at 490.0 ppt — 123× the EPA's enforceable limit of 4 ppt.
Most affected states
| # | State | Systems above EPA limits |
|---|---|---|
| 1 | California | 167 |
| 2 | Florida | 157 |
| 3 | New Jersey | 156 |
| 4 | Pennsylvania | 119 |
| 5 | North Carolina | 115 |
| 6 | Massachusetts | 106 |
| 7 | Texas | 103 |
| 8 | Alabama | 79 |
Full rankings: the 100 most-contaminated systems nationally, by compound, and by state. Per-state detail: browse all states.
03How to cite us
Our figures and presentation are free to cite and reference with attribution and a link to checkpfas.com. The underlying EPA UCMR 5 data is public domain. Suggested attribution:
CheckPFAS analysis of EPA UCMR 5 data (checkpfas.com)
When citing a specific figure, please link to the relevant page (for example, a state page or the rankings) so readers can verify it. We're happy to be quoted or to provide a custom data extract — see media contact below.
04Methodology, in brief
Figures come from the EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), which required large public water systems to test for 29 PFAS compounds between 2023 and 2025. "Above EPA limits" means a system measured at least one compound above the federal Maximum Contaminant Level finalized in 2024 (4 ppt for PFOA and PFOS; 10 ppt for PFHxS, PFNA, and GenX). Values reflect the highest single sample reported at a system's entry point.
05Data access
- · EPA UCMR 5 raw occurrence data (the original public dataset)
- · National & per-compound rankings on CheckPFAS
- · Per-state breakdowns and ZIP-level lookup
- · Custom extracts (a county, utility list, or single compound) on request — email us
Media contact
Get in touch
CheckPFAS is an independent, free public-interest project. We respond to press inquiries promptly. For our sourcing rubric and corrections policy, see our editorial standards.