What was found in ZIP 98166
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 1054 µg/L 11% of the EPA limit 10000 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 1/4 | SYR4 |
| Fluoride | 795 µg/L 20% of the EPA limit 4000 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012
Highest in the ZIP: 890 µg/L — HIGHLINE WATER DISTRICT · 100,170 people · 2015 | 2/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 50.606 µg/L 84% of the EPA limit 60 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 4/4 | SYR4 |
| TTHM | 49.723 µg/L 62% of the EPA limit 80 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 4/4 | SYR4 |
| Chloroform | 45.3 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019
Highest in the ZIP: 46.26 µg/L — KING COUNTY WATER DISTRICT #20 · 48,469 people · 2019 | 4/4 | SYR4 |
| Trichloroacetic Acid | 29.75 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 4/4 | SYR4 |
| Dichloroacetic Acid | 23.5 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 4/4 | SYR4 |
| Barium | 3.48 µg/L 0.2% of the EPA limit 2000 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012
Highest in the ZIP: 10 µg/L — HIGHLINE WATER DISTRICT · 100,170 people · 2015 | 2/4 | SYR4 |
| Arsenic | 8.08 µg/L 81% of the EPA limit 10 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012 | 2/4 | SYR4 |
| Bromodichloromethane | 2.7465 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019
Highest in the ZIP: 5.558 µg/L — HIGHLINE WATER DISTRICT · 100,170 people · 2019 | 4/4 | SYR4 |
| Dibromochloromethane | 1.922 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019
Highest in the ZIP: 4.72 µg/L — KING COUNTY WATER DISTRICT #49 · 23,492 people · 2019 | 4/4 | SYR4 |
| Copper | 4.35 µg/L 0.3% of the EPA limit 1300 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012 | 1/4 | SYR4 |
| Monochloroacetic Acid | 3.515 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019
Highest in the ZIP: 3.8715 µg/L — KING COUNTY WATER DISTRICT #20 · 48,469 people · 2019 | 4/4 | SYR4 |
| Nitrite | 2 µg/L 0.2% of the EPA limit 1000 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019 | 1/4 | SYR4 |
| Bromoform | 1.3845 µg/L No EPA limit set Highest in the ZIP: KING COUNTY WATER DISTRICT #49 · 23,492 people · 2019 | 3/4 | SYR4 |
| Dibromoacetic Acid | 0.7886 µg/L No EPA limit set Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2019
Highest in the ZIP: 1.3285 µg/L — KING COUNTY WATER DISTRICT #49 · 23,492 people · 2019 | 4/4 | SYR4 |
| Chromium | 1.2 µg/L 1.2% of the EPA limit 100 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012 | 1/4 | SYR4 |
| Selenium | 1.2 µg/L 2.4% of the EPA limit 50 µg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2012 | 1/4 | SYR4 |
| Lead | 0.0016 mg/L 11% of the EPA limit 0.0150 mg/L Main supplier: SEATTLE PUBLIC UTILITIES · 1,161,961 people · 2025 | 2/4 | LCR |
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 the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
Water suppliers serving ZIP 98166
| Supplier | State | Population served |
|---|---|---|
| SEATTLE PUBLIC UTILITIES | WA | 1,161,961 |
| HIGHLINE WATER DISTRICT | WA | 100,170 |
| KING COUNTY WATER DISTRICT #20 | WA | 48,469 |
| KING COUNTY WATER DISTRICT #49 | WA | 23,492 |
Frequently asked questions about ZIP 98166 tap water
Is the tap water in ZIP 98166 safe to drink?
EPA testing detected 19 contaminants across the water suppliers serving ZIP 98166. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 98166?
4 public water suppliers report EPA drinking-water monitoring for ZIP 98166. Each is listed above with its population served.
What contaminants are in ZIP 98166's water?
EPA monitoring detected Nitrate, Fluoride, Total Haloacetic Acids (HAA5), TTHM, Chloroform, and others across this ZIP's suppliers. The full list with levels and sources is above.