What was found in Charleston'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 | 1073 µg/L 27% of the EPA limit 4000 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Nitrate | 500 µg/L 5% of the EPA limit 10000 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Copper | 91 µg/L 7% of the EPA limit 1300 µg/L Main supplier: CHARLESTON · 17,286 people · 2017
Highest in the city: 335.15 µg/L — EASTERN ILLINOIS UNIVERSITY · 5,500 people · 2017 | 3/3 | SYR4 |
| TTHM | 35.33 µg/L 44% of the EPA limit 80 µg/L Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 89.99 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Chloroform | 26.05 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 75.045 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 16.14 µg/L 27% of the EPA limit 60 µg/L Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 35.565 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Lead | 25.4 µg/L 169% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: CHARLESTON · 17,286 people · 2017
Highest in the city: 34.68 µg/L — EASTERN ILLINOIS UNIVERSITY · 5,500 people · 2017 | 3/3 | SYR4 |
| Dichloroacetic Acid | 8.616 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 23.575 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Barium | 17 µg/L 0.9% of the EPA limit 2000 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Trichloroacetic Acid | 2.44 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 16.685 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Monobromoacetic Acid | 11.825 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019 | 2/3 | SYR4 |
| Bromodichloromethane | 6.928 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 11.456 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Selenium | 9.7 µg/L 19% of the EPA limit 50 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Monochloroacetic Acid | 5.068 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019 | 2/3 | SYR4 |
| Dibromochloromethane | 3.7017 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019
Highest in the city: 3.80585 µg/L — EMBARRAS AREA WATER DISTRICT · 3,750 people · 2019 | 3/3 | SYR4 |
| Bromate | 3.67 µg/L 37% of the EPA limit 10 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Dibromoacetic Acid | 2.5615 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019 | 3/3 | SYR4 |
| Bromoform | 1.713 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Arsenic | 1.39 µg/L 14% of the EPA limit 10 µg/L Main supplier: CHARLESTON · 17,286 people · 2019 | 1/3 | SYR4 |
| Combined Radium (-226 And -228) | 0.7070 pCi/L 14% of the EPA limit 5 pCi/L Main supplier: CHARLESTON · 17,286 people · 2014 | 1/3 | SYR4 |
| Pfpea | 0.0032 µg/L No EPA limit set Main supplier: CHARLESTON · 17,286 people · 2025 | 1/3 | UCMR-5 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L Main supplier: CHARLESTON · 17,286 people · 2025 | 3/3 | 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 Charleston
| Supplier | Population served |
|---|---|
| CHARLESTON | 17,286 |
| EASTERN ILLINOIS UNIVERSITY | 5,500 |
| EMBARRAS AREA WATER DISTRICT | 3,750 |
Frequently asked questions about Charleston tap water
Is Charleston tap water safe to drink?
EPA testing detected 22 contaminants in the water serving Charleston. 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 Charleston?
3 public water suppliers report drinking-water monitoring for Charleston, Illinois to the EPA. Each is listed above with its population served.
What contaminants are in Charleston's water?
The contaminants EPA monitoring detected in Charleston include Fluoride, Nitrate, Copper, TTHM, Chloroform. 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.