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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Side-by-side EPA records for the two public water systems · EPA SDWIS/ECHO 2026Q2 · UCMR5 (2023–2026, July 2026 release) · SYR4 six-year review 2012–2019 · methodology
SEATTLE PUBLIC UTILITIES · serves 1,161,961
No EPA system match
Not graded: we have not matched San Francisco to a live EPA public water system. Find its utility report →
| Metric | Seattle | San Francisco |
|---|---|---|
| Grade / score | A · 100/100 | Not graded |
| Health-based EPA violations, last 5 yrs | 0 | no data |
| Health-based violations unresolved | 0 | no data |
| Monitoring / reporting violations, last 5 yrs | 0 | no data |
| Lead 90th percentile (action level 15 ppb) | 1.6 ppb (2025–2025) | no data |
| PFAS detected (UCMR5 2023–2026) | None detected | not sampled |
| Primary water source | Surface water | Not reported |
| Population served | 1,161,961 | no data |
| EPA PWSID | WA5377050 | no data |
Green = the better value where the two systems differ. Lead and PFAS figures describe water leaving the plant, not any individual tap.
We can only grade Seattle: San Francisco has not been matched to an EPA water system, so a fair comparison is not possible yet.
Seattle grades A (100/100): no health-based EPA violations in the last five years, lead 90th percentile 1.6 ppb, no PFAS detected.
San Francisco is not yet matched to an EPA water system; check the utility's Consumer Confidence Report.