What was found in Lewiston's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 31600 µg/L 316% of the EPA limit, in the worst sample — 10000 µg/L | 5/9 | SYR4 |
| Nitrate-Nitrite | 7420 µg/L 74% of the EPA limit 10000 µg/L | 4/9 | SYR4 |
| Fluoride | 3100 µg/L 78% of the EPA limit 4000 µg/L | 9/9 | SYR4 |
| Nitrite | 377 µg/L 38% of the EPA limit 1000 µg/L | 1/9 | SYR4 |
| Barium | 135 µg/L 6.8% of the EPA limit 2000 µg/L | 9/9 | SYR4 |
| Copper | 57.4 µg/L 4.4% of the EPA limit 1300 µg/L | 2/9 | SYR4 |
| TTHM | 53.1 µg/L 66% of the EPA limit 80 µg/L | 4/9 | SYR4 |
| Total Haloacetic Acids (HAA5) | 47.1 µg/L 79% of the EPA limit 60 µg/L | 3/9 | SYR4 |
| Lithium | 43.8 µg/L No EPA limit set | 2/9 | UCMR-5 |
| Combined Uranium | 28.4 µg/L 95% of the EPA limit 30 µg/L | 3/9 | SYR4 |
| Gross Beta Particle Activity | 8.36 pCi/L No EPA limit set | 2/9 | SYR4 |
| Gross Alpha, Excl. Radon And U | 7.5 pCi/L 50% of the EPA limit 15 pCi/L | 4/9 | SYR4 |
| Chloroform | 6.31 µg/L No EPA limit set | 1/9 | SYR4 |
| Selenium | 3.52 µg/L 7% of the EPA limit 50 µg/L | 5/9 | SYR4 |
| Bromodichloromethane | 3.2 µg/L No EPA limit set | 1/9 | SYR4 |
| Chromium | 3.1 µg/L 3.1% of the EPA limit 100 µg/L | 8/9 | SYR4 |
| Lead | 2.5 µg/L 17% of the EPA limit 15 µg/L | 2/9 | SYR4 |
| Arsenic | 2.38 µg/L 24% of the EPA limit 10 µg/L | 7/9 | SYR4 |
| Picloram | 1.41 µg/L 0.3% of the EPA limit 500 µg/L | 2/9 | SYR4 |
| Combined Radium (-226 And -228) | 1.382 pCi/L 28% of the EPA limit 5 pCi/L | 7/9 | SYR4 |
| Dibromochloromethane | 1.15 µg/L No EPA limit set | 1/9 | SYR4 |
| Cadmium | 1.07 µg/L 21% of the EPA limit 5 µg/L | 1/9 | SYR4 |
| Toluene | 0.7800 µg/L 0.1% of the EPA limit 1000 µg/L | 1/9 | SYR4 |
| PFBS | 0.0056 µg/L No EPA limit set | 1/9 | UCMR-5 |
| Pfpea | 0.0047 µg/L No EPA limit set | 1/9 | UCMR-5 |
| Pfhxa | 0.0043 µg/L No EPA limit set | 1/9 | UCMR-5 |
| Lead | 0.0010 mg/L 6.7% of the EPA limit 0.0150 mg/L | 9/9 | LCR |
| Asbestos | -0.13 MFL -1.8% of the EPA limit 7 MFL | 2/9 | SYR4 |
Water suppliers serving Lewiston
| Supplier | Population served |
|---|---|
| LEWISTON ORCHARDS IRRIGATION DIST | 20,000 |
| LEWISTON CITY OF | 15,001 |
| RED PHEASANT WATER COMPANY LLC | 480 |
| COUGAR RIDGE WATER & SEWER | 173 |
| EAGLES POINTE SUBDIVISION | 110 |
| WAHA GLEN WATER DIST | 100 |
| EATON MOBILE HOME COURT | 94 |
| RED ROCK WATER LLC | 60 |
| VIEW POINT SUBDIVISION | 56 |
Frequently asked questions about Lewiston tap water
Is Lewiston tap water safe to drink?
EPA testing detected 28 contaminants in the water serving Lewiston. 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 Lewiston?
9 public water suppliers report drinking-water monitoring for Lewiston, Idaho to the EPA. Each is listed above with its population served.
What contaminants are in Lewiston's water?
The contaminants EPA monitoring detected in Lewiston include Nitrate, Nitrate-Nitrite, Fluoride, Nitrite, Barium. The full list, with the highest level found 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.