What was found in Herculaneum'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-Nitrite | 1040 µg/L 10% of the EPA limit 10000 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Fluoride | 653 µg/L 16% of the EPA limit 4000 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Copper | 159.09999999999948 µg/L 12% of the EPA limit 1300 µg/L Main supplier: HERCULANEUM PWS · 5,000 people · 2017 | 2/2 | SYR4 |
| TTHM | 75.5 µg/L 94% of the EPA limit 80 µg/L Main supplier: HERCULANEUM PWS · 5,000 people · 2019 | 2/2 | SYR4 |
| Chloroform | 39.425000000000004 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 29.959999999999997 µg/L 50% of the EPA limit 60 µg/L Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 35.279999999999994 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Barium | 28.455 µg/L 1.4% of the EPA limit 2000 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 24 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019 | 2/2 | SYR4 |
| Lithium | 22 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2024 | 1/2 | UCMR-5 |
| Dichloroacetic Acid | 17.799999999999997 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 19.15 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Lead | 18.483999999999988 µg/L 123% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: HERCULANEUM PWS · 5,000 people · 2017 | 2/2 | SYR4 |
| Dibromochloromethane | 15.835 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 18.11 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 9.48 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 12.540000000000001 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 9.78 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 11.6 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 5.208 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 6.733999999999997 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 4.776999999999999 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 4.9475 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Bromoform | 3.6600000000000006 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2019
Highest in the city: 3.7975 µg/L — JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 2/2 | SYR4 |
| Chromium | 2.95 µg/L 3% of the EPA limit 100 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Arsenic | 2.1904999999999997 µg/L 22% of the EPA limit 10 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Carbon Tetrachloride | 1.08 µg/L 22% of the EPA limit 5 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Atrazine | 0.6675 µg/L 22% of the EPA limit 3 µg/L Highest in the city: JEFFERSON COUNTY WATER AUTHORITY · 25 people · 2019 | 1/2 | SYR4 |
| Pfba | 0.0091 µg/L No EPA limit set Main supplier: HERCULANEUM PWS · 5,000 people · 2024 | 1/2 | UCMR-5 |
| Lead | 0.0014 mg/L 9.5% of the EPA limit 0.0150 mg/L Main supplier: HERCULANEUM PWS · 5,000 people · 2023 | 1/2 | 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 Herculaneum
| Supplier | Population served |
|---|---|
| HERCULANEUM PWS | 5,000 |
| JEFFERSON COUNTY WATER AUTHORITY | 25 |
Frequently asked questions about Herculaneum tap water
Is Herculaneum tap water safe to drink?
EPA testing detected 23 contaminants in the water serving Herculaneum. 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 Herculaneum?
2 public water suppliers report drinking-water monitoring for Herculaneum, Missouri to the EPA. Each is listed above with its population served.
What contaminants are in Herculaneum's water?
The contaminants EPA monitoring detected in Herculaneum include Nitrate-Nitrite, 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.