Seattle has the 5th best tap water of the 100 biggest US cities

I ranked tap water in the 100 biggest US cities using EPA and utility data, scoring each city’s main water system on lead, PFAS, other regulated contaminants and EPA violations. Seattle Public Utilities came 5th best.

The chart shows lead. Every lead result reported to EPA since 2016 is under 5 ppb, against an action level of 15. In SPU’s 2025 round, 9 in 10 homes were at or below 1.6 ppb and none of the 52 was over the action level. SPU’s inventory lists no lead service lines, though SPU says a few homes may still have short lead connectors.

No PFAS in EPA’s tests and no violations on EPA’s record. Where it lost points was chlorine byproducts: TTHMs averaged 34 ppb (limit 80) and HAA5 28 ppb (limit 60).

This covers SPU’s own customers. The suburbs that buy SPU water test separately and aren’t in this score.

Full list and method: tapwaterdata.com/rankings/cities