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Tap water quality report

Seattle Public Utilities

EPA monitoring tested this supplier for 104 contaminants and detected 18. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

104
contaminants tested
18
detected
1,161,961
people served
4
health-based violations
Washington rankingsLead in WashingtonPFAS in Washington
Water source
Surface water
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.

4
health-based violations
29
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2015-12-01
TT Health-based Resolved 2015-12-01
TT Health-based Archived 1995-01-01 → 2001-02-01
TT Health-based Archived 1995-01-01 → 2001-02-01
MR Monitoring Resolved 2007-01-01 → 2007-12-31
MR Monitoring Resolved 2007-01-01 → 2007-12-31
MR Monitoring Resolved 2007-01-01 → 2007-12-31
MR Monitoring Resolved 2007-01-01 → 2007-12-31
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
TTHM
49.723 µg/L 62%
of the EPA limit 80 µg/L
worst single sample: 90.76 µg/L
375/375 SYR4 2012–2019
Chloroform
45.3 µg/L
No EPA limit set
worst single sample: 87.4 µg/L
373/375 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
50.606 µg/L 84%
of the EPA limit 60 µg/L
worst single sample: 85.2 µg/L
367/367 SYR4 2012–2019
Dichloroacetic Acid
23.5 µg/L
No EPA limit set
worst single sample: 34 µg/L
361/361 SYR4 2012–2019
Trichloroacetic Acid
29.75 µg/L
No EPA limit set
worst single sample: 51.2 µg/L
358/358 SYR4 2012–2019
Bromodichloromethane
2.7465 µg/L
No EPA limit set
worst single sample: 9.19 µg/L
308/311 SYR4 2012–2019
Monochloroacetic Acid
3.515 µg/L
No EPA limit set
worst single sample: 5.45 µg/L
126/355 SYR4 2012–2019
Lead
0.0016 mg/L 11%
of the EPA limit 0.0150 mg/L
 30/30 LCR 2025
Nitrate
1054 µg/L 11%
of the EPA limit 10000 µg/L
worst single sample: 1180 µg/L
26/44 SYR4 2012–2019
Dibromochloromethane
1.922 µg/L
No EPA limit set
worst single sample: 1.95 µg/L
9/381 SYR4 2012–2019
Arsenic
8.08 µg/L 81%
of the EPA limit 10 µg/L
worst single sample: 8.1 µg/L
3/3 SYR4 2012
Barium
3.48 µg/L 0.2%
of the EPA limit 2000 µg/L
worst single sample: 3.5 µg/L
3/3 SYR4 2012
Copper
4.35 µg/L 0.3%
of the EPA limit 1300 µg/L
worst single sample: 4.4 µg/L
2/2 SYR4 2012
Dibromoacetic Acid
0.7886 µg/L
No EPA limit set
worst single sample: 0.7980 µg/L
2/376 SYR4 2012–2019
Fluoride
795 µg/L 20%
of the EPA limit 4000 µg/L
worst single sample: 800 µg/L
2/2 SYR4 2012
Chromium
1.2 µg/L 1.2%
of the EPA limit 100 µg/L
 1/3 SYR4 2012
Nitrite
2 µg/L 0.2%
of the EPA limit 1000 µg/L
 1/21 SYR4 2012–2019
Selenium
1.2 µg/L 2.4%
of the EPA limit 50 µg/L
 1/3 SYR4 2012
86 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromoformChlorobenzeneCyanideCadmiumCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEthylene DibromideEndrinEthylbenzeneGlyphosateGross Beta Particle ActivityHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorMonobromoacetic AcidNetfosaaNfdhaNmefosaaNitrate-NitritePfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
Winsome Williams

Frequently asked questions about Seattle Public Utilities

Is Seattle Public Utilities tap water safe to drink?

EPA monitoring detected 18 contaminants in Seattle Public Utilities'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 Seattle Public Utilities's water?

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

How many people does Seattle Public Utilities serve?

Seattle Public Utilities reports serving 1,161,961 people in Washington, per its EPA record.

Has Seattle Public Utilities had any water quality violations?

The EPA has 29 violations on file for Seattle Public Utilities, of which 4 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.