What was found in Thompson Falls'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 |
|---|---|---|---|
| Fluoride | 67.5 µg/L 1.7% of the EPA limit 4000 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2018
Highest in the city: 1067.5 µg/L — SALISH SHORES TRADE WINDS COMM VILLAGE · 215 people · 2019 | 4/4 | SYR4 |
| Nitrate-Nitrite | 515 µg/L 5.1% of the EPA limit 10000 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 4/4 | SYR4 |
| Nitrate | 510 µg/L 5.1% of the EPA limit 10000 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2015 | 2/4 | SYR4 |
| Copper | 302 µg/L 23% of the EPA limit 1300 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019
Highest in the city: 365 µg/L — NORTH SHORE ESTATES HOA · 65 people · 2019 | 4/4 | SYR4 |
| Barium | 286 µg/L 14% of the EPA limit 2000 µg/L Highest in the city: NORTH SHORE ESTATES HOA · 65 people · 2019 | 2/4 | SYR4 |
| Arsenic | 1.95 µg/L 20% of the EPA limit 10 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2018
Highest in the city: 35 µg/L — SALISH SHORES TRADE WINDS COMM VILLAGE · 215 people · 2019 | 3/4 | SYR4 |
| Lead | 2 µg/L 13% of the EPA limit 15 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019
Highest in the city: 4.8 µg/L — SALISH SHORES TRADE WINDS COMM VILLAGE · 215 people · 2018 | 4/4 | SYR4 |
| Gross Alpha, Excl. Radon And U | 4.05 pCi/L 27% of the EPA limit 15 pCi/L Highest in the city: NORTH SHORE ESTATES HOA · 65 people · 2019 | 3/4 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 3.96 µg/L 66% of the EPA limit 6 µg/L Highest in the city: SALISH SHORES TRADE WINDS COMM VILLAGE · 215 people · 2019 | 1/4 | SYR4 |
| TTHM | 3.35 µg/L 4.2% of the EPA limit 80 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Combined Uranium | 1 µg/L 3.3% of the EPA limit 30 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2015
Highest in the city: 3.095 µg/L — NORTH SHORE ESTATES HOA · 65 people · 2019 | 3/4 | SYR4 |
| Combined Radium (-226 And -228) | 1.8 pCi/L 36% of the EPA limit 5 pCi/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2015
Highest in the city: 3.025 pCi/L — SALISH SHORES TRADE WINDS COMM VILLAGE · 215 people · 2016 | 4/4 | SYR4 |
| Chloroform | 2.57 µg/L No EPA limit set Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 2.2 µg/L 3.7% of the EPA limit 60 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Dichloroacetic Acid | 2.04 µg/L No EPA limit set Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Toluene | 1.4 µg/L 0.1% of the EPA limit 1000 µg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2018 | 1/4 | SYR4 |
| Bromodichloromethane | 0.5955 µg/L No EPA limit set Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Dibromoacetic Acid | 0.3700 µg/L No EPA limit set Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2019 | 1/4 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: THOMPSON FALLS CITY OF · 1,950 people · 2025
Highest in the city: 0.0010 mg/L — WOODSIDE PARK COUNTY WATER AND SEWER DIS · 115 people · 2017 | 4/4 | 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.
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 Thompson Falls
| Supplier | Population served |
|---|---|
| THOMPSON FALLS CITY OF | 1,950 |
| SALISH SHORES TRADE WINDS COMM VILLAGE | 215 |
| WOODSIDE PARK COUNTY WATER AND SEWER DIS | 115 |
| NORTH SHORE ESTATES HOA | 65 |
Frequently asked questions about Thompson Falls tap water
Is Thompson Falls tap water safe to drink?
EPA testing detected 19 contaminants in the water serving Thompson Falls. 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 Thompson Falls?
4 public water suppliers report drinking-water monitoring for Thompson Falls, Montana to the EPA. Each is listed above with its population served.
What contaminants are in Thompson Falls's water?
The contaminants EPA monitoring detected in Thompson Falls include Fluoride, Nitrate-Nitrite, Nitrate, 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.