EPA UCMR 5 · Updated Jan 2026 · 6,151 systems with detections · 14,090 ZIP codes
Is there PFAS in your
tap water?
Enter your ZIP code to see what EPA's national testing program found in your local water utility — what was detected, at what levels, and what (if anything) is worth doing about it.
Last looked up: — Look again →
Free. No account needed. Data from EPA UCMR 5 (updated Jan 2026).
Don't know your ZIP? Search by utility name or city →
The Short Version
What Are PFAS?
Per- and polyfluoroalkyl substances (PFAS) are a family of more than 12,000 synthetic chemicals used since the 1940s in non-stick cookware, waterproof clothing, food packaging, and firefighting foam. They're called "forever chemicals" because they resist breakdown — accumulating in water, soil, and the human body over time. Long-term exposure at higher concentrations has been linked to kidney cancer, thyroid disease, immune suppression, and developmental harm in children.
EPA's UCMR 5 program (2023–2025) tested roughly 10,000 public water systems for 29 PFAS compounds. This site makes that data searchable by ZIP code.
Compound-by-compound health effects and EPA limits →Explore
Go deeper on the data
Rankings
Most contaminated systems
The 100 worst U.S. water systems, ranked by how far they exceed EPA limits.
See the rankings →Filters
Which filter removes PFAS
Every method compared by removal rate, cost, and NSF certification.
Compare filters →Health
Health effects by condition
Cancer, cholesterol, thyroid, fertility — what the evidence actually shows.
Explore health effects →By city
Find your city
City-level results aggregated across every utility and ZIP code.
Browse cities →By State
Most affected states
Interactive Data
Every county in America,
colored by max PFAS detected.
Click any county to jump to ZIP codes and testing results — powered by EPA UCMR 5.
Open the national mapLatest from Learn
PFAS News, Guides & Research
Does a Brita Filter Remove PFAS? (The Honest Answer)
Standard Brita pitchers are not certified to remove PFAS. Here's what Brita actually filters, what the testing shows, and which filters do remove PFAS from drinking water.
Do Refrigerator Filters Remove PFAS?
Most refrigerator water filters are not certified to remove PFAS. Here's how to check your fridge filter's certification — and what to use if it falls short.
Does Boiling Water Remove PFAS? (No — Here's Why)
Boiling water does not remove PFAS — and can slightly concentrate it. Here's the science on why heat doesn't work, and what actually removes forever chemicals.
How This Works
Source
Data from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule, 5th cycle), released January 2026. Testing period: January 2023 – December 2025.
Coverage
~10,000 public water systems tested for 29 PFAS compounds. Small systems (<25 people) and private wells are not included in this dataset.
Limitations
Results reflect entry-point measurements at the treatment plant. Building plumbing and private wells may differ. CheckPFAS is not affiliated with the EPA.