What was found in Wilmington'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 | 6195 µg/L 62% of the EPA limit 10000 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Nitrate-Nitrite | 2800 µg/L 28% of the EPA limit 10000 µg/L Main supplier: WILMINGTON · 5,700 people · 2018 | 1/2 | SYR4 |
| Fluoride | 1230 µg/L 31% of the EPA limit 4000 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Copper | 209 µg/L 16% of the EPA limit 1300 µg/L Main supplier: WILMINGTON · 5,700 people · 2019
Highest in the city: 870.9 µg/L — PATTERSON (INC AS WILMINGTON) · 320 people · 2018 | 2/2 | SYR4 |
| TTHM | 77.45 µg/L 97% of the EPA limit 80 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Chloroform | 64.314 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Lead | 61.1 µg/L 407% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 41.12 µg/L 69% of the EPA limit 60 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 28.9 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Combined Radium (-226 And -228) | 20.825 pCi/L 417% of the EPA limit, at the 95th percentile of samples — 5 pCi/L Main supplier: WILMINGTON · 5,700 people · 2018 | 1/2 | SYR4 |
| Barium | 16.5 µg/L 0.8% of the EPA limit 2000 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 15.575 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 12.04 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Dibromochloromethane | 10.915 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 8.7815 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Selenium | 7.625 µg/L 15% of the EPA limit 50 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Chromium | 5 µg/L 5% of the EPA limit 100 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Dibromoacetic Acid | 4.856 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Arsenic | 3.62 µg/L 36% of the EPA limit 10 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Bromoform | 3.535 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 2.945 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Atrazine | 0.3500 µg/L 12% of the EPA limit 3 µg/L Main supplier: WILMINGTON · 5,700 people · 2019 | 1/2 | SYR4 |
| Pfba | 0.0057 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2025 | 1/2 | UCMR-5 |
| Lead | 0.0050 mg/L 33% of the EPA limit 0.0150 mg/L Main supplier: WILMINGTON · 5,700 people · 2025 | 2/2 | LCR |
| Pfpea | 0.0045 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2025 | 1/2 | UCMR-5 |
| Pfhxa | 0.0040 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2025 | 1/2 | UCMR-5 |
| PFBS | 0.0031 µg/L No EPA limit set Main supplier: WILMINGTON · 5,700 people · 2025 | 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 Wilmington
| Supplier | Population served |
|---|---|
| WILMINGTON | 5,700 |
| PATTERSON (INC AS WILMINGTON) | 320 |
Frequently asked questions about Wilmington tap water
Is Wilmington tap water safe to drink?
EPA testing detected 27 contaminants in the water serving Wilmington. 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 Wilmington?
2 public water suppliers report drinking-water monitoring for Wilmington, Illinois to the EPA. Each is listed above with its population served.
What contaminants are in Wilmington's water?
The contaminants EPA monitoring detected in Wilmington 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.