What was found in Alton'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 | 5292 µg/L 53% of the EPA limit 10000 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 1/4 | SYR4 |
| Fluoride | 1020 µg/L 26% of the EPA limit 4000 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 1/4 | SYR4 |
| Copper | 356.3999999999999 µg/L 27% of the EPA limit 1300 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2017 | 4/4 | SYR4 |
| TTHM | 91.66499999999999 µg/L 115% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 4/4 | SYR4 |
| Chloroform | 70.755 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 54.489999999999995 µg/L 91% of the EPA limit 60 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019
Highest in the city: 56.25 µg/L — ENCHANTED VILLAGE · 720 people · 2019 | 4/4 | SYR4 |
| Dichloroacetic Acid | 29.65999999999999 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 4/4 | SYR4 |
| Trichloroacetic Acid | 22.294999999999998 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019
Highest in the city: 24.764999999999993 µg/L — ENCHANTED VILLAGE · 720 people · 2019 | 4/4 | SYR4 |
| Bromodichloromethane | 20.3 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 4/4 | SYR4 |
| Lead | 15.74999999999999 µg/L 105% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2017
Highest in the city: 16.86999999999999 µg/L — OAK GROVE MHP - MADISON COUNTY · 138 people · 2019 | 4/4 | SYR4 |
| Monobromoacetic Acid | 3.2949999999999986 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019
Highest in the city: 13.658999999999999 µg/L — OAK GROVE MHP - MADISON COUNTY · 138 people · 2019 | 4/4 | SYR4 |
| Lithium | 9.6 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2024 | 1/4 | UCMR-5 |
| Monochloroacetic Acid | 5.274999999999999 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019
Highest in the city: 6.2299999999999995 µg/L — FOSTERBURG PWD · 7,940 people · 2019 | 4/4 | SYR4 |
| Dibromochloromethane | 5.95 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 4/4 | SYR4 |
| Dibromoacetic Acid | 1.7 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019
Highest in the city: 1.975 µg/L — FOSTERBURG PWD · 7,940 people · 2019 | 3/4 | SYR4 |
| Arsenic | 1 µg/L 10% of the EPA limit 10 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 1/4 | SYR4 |
| Atrazine | 0.3000 µg/L 10% of the EPA limit 3 µg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2019 | 1/4 | SYR4 |
| Pfba | 0.0178 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2024 | 2/4 | UCMR-5 |
| Pfhxa | 0.0062 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2024 | 1/4 | UCMR-5 |
| Pfpea | 0.0056 µg/L No EPA limit set Main supplier: IL AMERICAN-ALTON · 46,127 people · 2024 | 2/4 | UCMR-5 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L Main supplier: IL AMERICAN-ALTON · 46,127 people · 2025 | 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 Alton
| Supplier | Population served |
|---|---|
| IL AMERICAN-ALTON | 46,127 |
| FOSTERBURG PWD | 7,940 |
| ENCHANTED VILLAGE | 720 |
| OAK GROVE MHP - MADISON COUNTY | 138 |
Frequently asked questions about Alton tap water
Is Alton tap water safe to drink?
EPA testing detected 21 contaminants in the water serving Alton. 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 Alton?
4 public water suppliers report drinking-water monitoring for Alton, Illinois to the EPA. Each is listed above with its population served.
What contaminants are in Alton's water?
The contaminants EPA monitoring detected in Alton include Nitrate, Fluoride, 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.