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How it works

1. Find your water utility

Your address is located with the free US Census Bureau geocoder, then matched against EPA's map of community water system service areas. If no boundary covers it, we fall back to the ZIP codes EPA lists for each utility. If nothing matches at all, the address is most likely on a private well.

2. Pull the public record

• PFAS: EPA's fifth Unregulated Contaminant Monitoring Rule (UCMR 5), which tested about 10,000 systems for 29 PFAS between 2023 and 2025.
• Violations: health-based violations from the last 10 years in EPA's Safe Drinking Water Information System (SDWIS).
• Lead: the utility's most recent 90th-percentile lead result reported under the Lead and Copper Rule.

3. Match a filter

PFAS above EPA's 4 ppt limit, or violations for nitrate, arsenic, fluoride or radioactive contaminants, point to reverse osmosis, since carbon filters don't reliably remove those. Elevated lead or microbial violations point to a filter certified to NSF/ANSI 53. Otherwise we suggest a certified carbon faucet filter, which handles taste and lead from home plumbing.

Where a product's certification is marked as verified, we checked it in the certifier's own directory. Other claims are the manufacturer's; confirm them on the listing.

Limits

Utility data describes water leaving the treatment plant and sampled across the system. It says nothing about your building's own pipes. The only way to know exactly what comes out of your tap is to test it.