- EPA's UCMR 5 testing looked for 30 contaminants here and found none.
Public EPA test results
What EPA records show for King County Water District #20
EPA WA5338950 · serves King County, WA · about 48,469 people (EPA SDWIS)
This report shows EPA's federal records for this water system: UCMR 5 testing, lead testing and violations. It isn't a test of the water at your tap, and it has no Water Score.
Public EPA test results
King County Water District #20 (EPA WA5338950)
What EPA records show for King County Water District #20, as of October 14, 2026
We found no health-based violations in EPA's records for this system (WA5338950) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for King County Water District #20 (SDWIS). Data as of October 14, 2026.
This system buys water from King County Water District #49 (WA5339800), Highline Water District (WA5340650), King County Water District #125 (WA5341998) and 1 more; see those systems' records.
Source: King County Water District #49 (WA5339800) report, Highline Water District (WA5340650) report, King County Water District #125 (WA5341998) report, Seattle Public Utilities (WA5377050) report. Data as of October 14, 2026.
EPA's UCMR 5 testing looked for 30 contaminants here and found none.
PFOA and PFOS were not detected at or above EPA's reporting level in EPA's UCMR 5 testing.
Source: EPA records (SDWIS, UCMR 5). SDWIS: data as of Oct 14, 2026. EPA UCMR 5 data, samples through June 2026.
Your water bill names your utility.
Does King County Water District #20 use chloramine?
We didn't find chloramine in King County Water District #20's EPA treatment records. That's not a complete list; your utility's annual water quality report says which disinfectant it uses.