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Tap water quality report

King County Water District No 90

EPA monitoring tested this supplier for 102 contaminants and detected 12. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

102
contaminants tested
12
detected
20,100
people served
6
health-based violations
Washington rankingsLead in WashingtonPFAS in Washington
Water source
SWP
Ownership
Local government
Counties served
King

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

6
health-based violations
262
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Archived 1992-07-01 → 1992-07-31
MCL Health-based Archived 1992-07-01 → 1992-07-31
MCL Health-based Archived 1992-07-01 → 1992-07-31
MCL Health-based Archived 1991-11-01 → 1991-11-30
MCL Health-based Archived 1991-11-01 → 1991-11-30
MCL Health-based Archived 1991-11-01 → 1991-11-30
Other Monitoring Resolved 2024-07-01
Other Monitoring Resolved 2021-07-01
MR Monitoring Resolved 2007-01-01 → 2007-12-31
MR Monitoring Resolved 2007-01-01 → 2007-12-31

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Chloroform
30.56 µg/L
No EPA limit set
worst single sample: 34.4 µg/L
112/113 SYR4 2012–2019
TTHM
33.559 µg/L 42%
of the EPA limit 80 µg/L
worst single sample: 37.39 µg/L
112/112 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
33.445 µg/L 56%
of the EPA limit 60 µg/L
worst single sample: 37.3 µg/L
112/112 SYR4 2012–2019
Bromodichloromethane
3.225 µg/L
No EPA limit set
worst single sample: 4.11 µg/L
111/113 SYR4 2012–2019
Dichloroacetic Acid
15.2 µg/L
No EPA limit set
worst single sample: 17.1 µg/L
110/110 SYR4 2012–2019
Trichloroacetic Acid
17.1 µg/L
No EPA limit set
worst single sample: 20.4 µg/L
110/110 SYR4 2012–2019
Dibromochloromethane
0.7560 µg/L
No EPA limit set
worst single sample: 0.9800 µg/L
25/113 SYR4 2012–2019
Monochloroacetic Acid
3.698 µg/L
No EPA limit set
worst single sample: 4 µg/L
25/112 SYR4 2012–2019
Lead
0.0012 mg/L 8%
of the EPA limit 0.0150 mg/L
 9/9 LCR 2025
Dibromoacetic Acid
1.0276 µg/L
No EPA limit set
worst single sample: 1.05 µg/L
2/112 SYR4 2012–2019
Arsenic
3.5 µg/L 35%
of the EPA limit 10 µg/L
 1/1 SYR4 2016
Fluoride
910 µg/L 23%
of the EPA limit 4000 µg/L
 1/1 SYR4 2016
90 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBariumBenzeneBenzo(A)PyreneBeryllium, TotalBromoformChlorobenzeneCopperCyanideCadmiumCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEndrinEthylbenzeneHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorMonobromoacetic AcidNetfosaaNfdhaNmefosaaNitrateNitrate-NitriteNitritePfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
Joshua Drummond

Frequently asked questions about King County Water District No 90

Is King County Water District No 90 tap water safe to drink?

EPA monitoring detected 12 contaminants in King County Water District No 90's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in King County Water District No 90's water?

EPA monitoring detected Chloroform, TTHM, Total Haloacetic Acids (HAA5), Bromodichloromethane, Dichloroacetic Acid, and others. The full list with the level and data source for each is above.

How many people does King County Water District No 90 serve?

King County Water District No 90 reports serving 20,100 people in Washington, per its EPA record.

Has King County Water District No 90 had any water quality violations?

The EPA has 262 violations on file for King County Water District No 90, of which 6 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.