What was found in Rock Island'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 | 2600 µg/L 26% of the EPA limit 10000 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 2800 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Nitrate-Nitrite | 2060 µg/L 21% of the EPA limit 10000 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2018 | 2/2 | SYR4 |
| Fluoride | 1184.5 µg/L 30% of the EPA limit 4000 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019 | 1/2 | SYR4 |
| Copper | 186 µg/L 14% of the EPA limit 1300 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2017
Highest in the city: 192.5 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2017 | 2/2 | SYR4 |
| TTHM | 71.365 µg/L 89% of the EPA limit 80 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 56 µg/L 93% of the EPA limit 60 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 69.85 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Chloroform | 63.875 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 34.85 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 51.85 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Barium | 35.65 µg/L 1.8% of the EPA limit 2000 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 23.52 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 23.63 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 13.84 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Lead | 4.76 µg/L 32% of the EPA limit 15 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2017
Highest in the city: 12.6 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2017 | 2/2 | SYR4 |
| Dibromochloromethane | 4.2654 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 11.377 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 8.383 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 3.796 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2019
Highest in the city: 5.3275 µg/L — ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 2/2 | SYR4 |
| Bromoform | 5.3078 µg/L No EPA limit set Highest in the city: ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 1/2 | SYR4 |
| Arsenic | 1.2 µg/L 12% of the EPA limit 10 µg/L Main supplier: ROCK ISLAND · 39,018 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 1 µg/L No EPA limit set Highest in the city: ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2019 | 1/2 | SYR4 |
| Combined Radium (-226 And -228) | 0.7520 pCi/L 15% of the EPA limit 5 pCi/L Highest in the city: ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2014 | 1/2 | SYR4 |
| Pfba | 0.0160 µg/L No EPA limit set Main supplier: ROCK ISLAND · 39,018 people · 2023 | 2/2 | UCMR-5 |
| Lead | 0.0056 mg/L 37% of the EPA limit 0.0150 mg/L Main supplier: ROCK ISLAND · 39,018 people · 2025 | 2/2 | LCR |
| PFOA | 0.0046 µg/L No EPA limit set Highest in the city: ROCK ISLAND ARSENAL, US ARMY · 7,800 people · 2023 | 1/2 | 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 Rock Island
| Supplier | Population served |
|---|---|
| ROCK ISLAND | 39,018 |
| ROCK ISLAND ARSENAL, US ARMY | 7,800 |
Frequently asked questions about Rock Island tap water
Is Rock Island tap water safe to drink?
EPA testing detected 22 contaminants in the water serving Rock Island. 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 Rock Island?
2 public water suppliers report drinking-water monitoring for Rock Island, Illinois to the EPA. Each is listed above with its population served.
What contaminants are in Rock Island's water?
The contaminants EPA monitoring detected in Rock Island include Nitrate, Nitrate-Nitrite, Fluoride, Copper, TTHM. 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.