What was found in Walla Walla'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 | 2775 µg/L 28% of the EPA limit 10000 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 7500 µg/L — SYDNEY HEIGHTS WATER ASSN · 130 people · 2019 | 13/15 | SYR4 |
| Nitrate-Nitrite | 1175 µg/L 12% of the EPA limit 10000 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 2907 µg/L — DIXIE WATER ASSOCIATION · 240 people · 2019 | 6/15 | SYR4 |
| Fluoride | 228 µg/L 5.7% of the EPA limit 4000 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 2423 µg/L — KOOSKOOSKIE CABIN OWNERS INC. · 45 people · 2019 | 11/15 | SYR4 |
| Copper | 51.48 µg/L 4% of the EPA limit 1300 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 707.809 µg/L — DIXIE WATER ASSOCIATION · 240 people · 2019 | 9/15 | SYR4 |
| Barium | 7.28 µg/L 0.4% of the EPA limit 2000 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 76.8 µg/L — WALLA WALLA UNIVERSITY · 1,273 people · 2013 | 13/15 | SYR4 |
| Total Haloacetic Acids (HAA5) | 26.8 µg/L 45% of the EPA limit 60 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019 | 4/15 | SYR4 |
| TTHM | 22.464 µg/L 28% of the EPA limit 80 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019 | 7/15 | SYR4 |
| Chloroform | 21.62 µg/L No EPA limit set Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019 | 4/15 | SYR4 |
| Trichloroacetic Acid | 17.24 µg/L No EPA limit set Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019 | 1/15 | SYR4 |
| Dichloroacetic Acid | 13.03 µg/L No EPA limit set Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019 | 3/15 | SYR4 |
| Bromoform | 6.305 µg/L No EPA limit set Highest in the city: VALLE LINDO HOMES · 787 people · 2019 | 6/15 | SYR4 |
| Gross Beta Particle Activity | 5.03 pCi/L No EPA limit set Highest in the city: SUMMERS CIRCLE WATER LLC · 82 people · 2015 | 1/15 | SYR4 |
| Dibromochloromethane | 0.6900 µg/L No EPA limit set Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 2.795 µg/L — WALLA WALLA UNIVERSITY · 1,273 people · 2019 | 6/15 | SYR4 |
| Lead | 1.88 µg/L 13% of the EPA limit 15 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 2.51 µg/L — DIXIE WATER ASSOCIATION · 240 people · 2019 | 5/15 | SYR4 |
| Bromodichloromethane | 1.87 µg/L No EPA limit set Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 2.47 µg/L — WALLA WALLA UNIVERSITY · 1,273 people · 2019 | 4/15 | SYR4 |
| Dibromoacetic Acid | 2.05 µg/L No EPA limit set Highest in the city: WALLA WALLA UNIVERSITY · 1,273 people · 2019 | 2/15 | SYR4 |
| Selenium | 1.09 µg/L 2.2% of the EPA limit 50 µg/L Highest in the city: WALLA WALLA UNIVERSITY · 1,273 people · 2013 | 1/15 | SYR4 |
| Arsenic | 0.3000 µg/L 3% of the EPA limit 10 µg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2019
Highest in the city: 1 µg/L — PRESCOTT TOWN OF · 522 people · 2012 | 3/15 | SYR4 |
| Carbon Tetrachloride | 0.9090 µg/L 18% of the EPA limit 5 µg/L Highest in the city: DIXIE WATER ASSOCIATION · 240 people · 2019 | 1/15 | SYR4 |
| Thallium, Total | 0.6100 µg/L 31% of the EPA limit 2 µg/L Highest in the city: CONSOLIDATED IRRIGATION DIST 14 · 1,555 people · 2016 | 1/15 | SYR4 |
| Beryllium, Total | 0.3000 µg/L 7.5% of the EPA limit 4 µg/L Highest in the city: CONSOLIDATED IRRIGATION DIST 14 · 1,555 people · 2016 | 1/15 | SYR4 |
| Picloram | 0.1140 µg/L 0% of the EPA limit 500 µg/L Highest in the city: SYDNEY HEIGHTS WATER ASSN · 130 people · 2019 | 1/15 | SYR4 |
| Lead | 0.0044 mg/L 29% of the EPA limit 0.0150 mg/L Main supplier: WALLA WALLA WATER DIVISION · 42,959 people · 2025
Highest in the city: 0.0150 mg/L — PROSPECT HEIGHTS COMM WATER ASSN · 40 people · 2024 | 15/15 | 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.
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 Walla Walla
| Supplier | Population served |
|---|---|
| WALLA WALLA WATER DIVISION | 42,959 |
| CONSOLIDATED IRRIGATION DIST 14 | 1,555 |
| WALLA WALLA UNIVERSITY | 1,273 |
| VALLE LINDO HOMES | 787 |
| GREEN TANK IRR DISTRICT 11 | 553 |
| PRESCOTT TOWN OF | 522 |
| HYDRO IRRIGATION DISTRICT NO 9 | 260 |
| BLALOCK ORCHARD DIST 10 | 250 |
| DIXIE WATER ASSOCIATION | 240 |
| BLALOCK ORCHARDS DIST 12 | 193 |
| SYDNEY HEIGHTS WATER ASSN | 130 |
| SUMMERS CIRCLE WATER LLC | 82 |
| KOOSKOOSKIE CABIN OWNERS INC. | 45 |
| PROSPECT HEIGHTS COMM WATER ASSN | 40 |
| RESER CREEK WATER SYSTEM | 26 |
Frequently asked questions about Walla Walla tap water
Is Walla Walla tap water safe to drink?
EPA testing detected 23 contaminants in the water serving Walla Walla. 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 Walla Walla?
15 public water suppliers report drinking-water monitoring for Walla Walla, Washington to the EPA. Each is listed above with its population served.
What contaminants are in Walla Walla's water?
The contaminants EPA monitoring detected in Walla Walla include Nitrate, Nitrate-Nitrite, Fluoride, Copper, Barium. 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.