EPA data · certification listings · checked 16 Oct 2026
What’s in your tap water, and which filters are certified for it
Type your ZIP code. We show what EPA’s testing found in your utility’s water, then the filters whose certification listing actually covers it. We don’t test products; we check the public listings.
Covers the 50 largest US water systems (69 million people, per EPA’s SDWIS). Not on the list? We’ll show you where to find your own utility’s report.
What the data shows
12 of 49
large systems had a sampling point averaging above EPA’s 4.0 ng/L limit for PFOA or PFOS in UCMR 5 testing. See all systems
11 of 41
filters that claim PFAS reduction have it confirmed in an IAPMO listing we checked. Browse filters
97
filters and softeners, each claim traced to the brand page and the certification listing, with dates. How we check
Three labels, one meaning each
- Certified (listing checked)The certifier’s public listing shows this claim for this model.
- Brand says certifiedThe brand says certified; IAPMO’s listing does not show it. NSF can be checked by hand.
- Brand claim onlyThe brand claims it without citing a certification.