What was found in Olympia's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 2512.5 µg/L 25% of the EPA limit 10000 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 4825 µg/L — BLACK LAKE BIBLE CAMP & CONF CTR · 477 people · 2018 | 17/20 | SYR4 |
| Nitrate-Nitrite | 2415 µg/L 24% of the EPA limit 10000 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 2800 µg/L — BLACK LAKE ACRES · 104 people · 2016 | 12/20 | SYR4 |
| Copper | 7 µg/L 0.5% of the EPA limit 1300 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 799 µg/L — CUYAMACA · 375 people · 2019 | 3/20 | SYR4 |
| Barium | 8.6 µg/L 0.4% of the EPA limit 2000 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 438 µg/L — BOSTON HARBOR · 1,153 people · 2012 | 4/20 | SYR4 |
| Fluoride | 100 µg/L 2.5% of the EPA limit 4000 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 295 µg/L — NISQUALLY-LESCHI & WEST NISQUALLY · 3,200 people · 2019 | 2/20 | SYR4 |
| TTHM | 9.225 µg/L 12% of the EPA limit 80 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 121.55 µg/L — TAMOSHAN · 260 people · 2019 | 10/20 | SYR4 |
| Chloroform | 4.3 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 115.1 µg/L — TAMOSHAN · 260 people · 2019 | 10/20 | SYR4 |
| Total Haloacetic Acids (HAA5) | 5.41 µg/L 9% of the EPA limit 60 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 66.3175 µg/L — TAMOSHAN · 260 people · 2019 | 7/20 | SYR4 |
| Trichloroacetic Acid | 1.8 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 41.7 µg/L — TAMOSHAN · 260 people · 2019 | 7/20 | SYR4 |
| Bromodichloromethane | 3.267 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 28.35 µg/L — BOSTON HARBOR · 1,153 people · 2019 | 10/20 | SYR4 |
| Dichloroacetic Acid | 2.68 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 21.7875 µg/L — TAMOSHAN · 260 people · 2019 | 7/20 | SYR4 |
| Monochloroacetic Acid | 10.26 µg/L No EPA limit set Highest in the city: TAMOSHAN · 260 people · 2019 | 3/20 | SYR4 |
| Dibromochloromethane | 2.204 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 9.38 µg/L — BOSTON HARBOR · 1,153 people · 2019 | 8/20 | SYR4 |
| Monobromoacetic Acid | 5.86 µg/L No EPA limit set Highest in the city: TAMOSHAN · 260 people · 2019 | 3/20 | SYR4 |
| Arsenic | 2 µg/L 20% of the EPA limit 10 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 4.8 µg/L — BOSTON HARBOR · 1,153 people · 2012 | 6/20 | SYR4 |
| Dibromoacetic Acid | 1.65 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 4.32 µg/L — BOSTON HARBOR · 1,153 people · 2019 | 4/20 | SYR4 |
| Lead | 3.42 µg/L 23% of the EPA limit 15 µg/L Highest in the city: CUYAMACA · 375 people · 2019 | 5/20 | SYR4 |
| Combined Radium (-226 And -228) | 2.58 pCi/L 52% of the EPA limit 5 pCi/L Highest in the city: NISQUALLY-LESCHI & WEST NISQUALLY · 3,200 people · 2016 | 2/20 | SYR4 |
| Gross Beta Particle Activity | 1.791 pCi/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019 | 1/20 | SYR4 |
| Bromoform | 0.5850 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2019
Highest in the city: 1.5 µg/L — CARLYON BEACH HOMEOWNERS · 1,273 people · 2019 | 6/20 | SYR4 |
| Xylenes, Total | 0.4000 µg/L 0% of the EPA limit 10000 µg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2016
Highest in the city: 1.23 µg/L — BOSTON HARBOR · 1,153 people · 2018 | 3/20 | SYR4 |
| Lead | 0.0034 mg/L 23% of the EPA limit 0.0150 mg/L Main supplier: OLYMPIA CITY OF · 126,966 people · 2025
Highest in the city: 0.0085 mg/L — CLOISTER · 29 people · 1997 | 20/20 | LCR |
| PFOS | 0.0058 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2024 | 1/20 | UCMR-5 |
| PFBS | 0.0048 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2024 | 1/20 | UCMR-5 |
| PFOA | 0.0043 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2024 | 1/20 | UCMR-5 |
| Pfhxa | 0.0040 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2024 | 1/20 | UCMR-5 |
| Pfpea | 0.0033 µg/L No EPA limit set Main supplier: OLYMPIA CITY OF · 126,966 people · 2024 | 1/20 | UCMR-5 |
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.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Olympia
| Supplier | Population served |
|---|---|
| OLYMPIA CITY OF | 126,966 |
| GRAND MOUND | 3,764 |
| NISQUALLY-LESCHI & WEST NISQUALLY | 3,200 |
| CARLYON BEACH HOMEOWNERS | 1,273 |
| BOSTON HARBOR | 1,153 |
| BLACK LAKE BIBLE CAMP & CONF CTR | 477 |
| CUYAMACA | 375 |
| TAMOSHAN | 260 |
| COUNTRY CLUB ESTATES 521 | 113 |
| BLACK LAKE ACRES | 104 |
| NORTH OFFUT LAKE WTR SERVICE | 97 |
| WOODARD PLACE | 94 |
| PIONEER | 84 |
| HAYNES ACRES DIVISION 1 | 74 |
| Ski View Estates | 47 |
| COOPER POINT ESTATES | 36 |
| Sexton | 35 |
| CLOISTER | 29 |
| DELPHI DAUBEL | 29 |
| SALT AIRE MOBILE TERRACE | 23 |
Frequently asked questions about Olympia tap water
Is Olympia tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Olympia. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Olympia?
20 public water suppliers report drinking-water monitoring for Olympia, Washington to the EPA. Each is listed above with its population served.
What contaminants are in Olympia's water?
The contaminants EPA monitoring detected in Olympia include Nitrate, Nitrate-Nitrite, Copper, Barium, Fluoride. The full list, with the level at the main supplier and the data source, is in the table above.
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.