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Tap water quality report

St. Charles, MO

EPA monitoring detected 19 contaminants across the 1 water supplier serving St. Charles. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
78,961
people served
19
contaminants found
Missouri rankings Lead in Missouri PFAS in Missouri

What was found in St. Charles'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.

ContaminantLevel vs EPA limitSuppliersSource
Fluoride
519 µg/L 13%
of the EPA limit 4000 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2017
1/1 SYR4
Barium
77.52499999999999 µg/L 3.9%
of the EPA limit 2000 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2017
1/1 SYR4
Lithium
45.1 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2024
1/1 UCMR-5
Total Haloacetic Acids (HAA5)
35.2 µg/L 59%
of the EPA limit 60 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Dichloroacetic Acid
27.869999999999976 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
TTHM
22.789999999999974 µg/L 28%
of the EPA limit 80 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Copper
21.759999999999998 µg/L 1.7%
of the EPA limit 1300 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2018
1/1 SYR4
Chloroform
20.35999999999999 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Nitrate-Nitrite
20 µg/L 0.2%
of the EPA limit 10000 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Monochloroacetic Acid
11.076 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Monobromoacetic Acid
7.34 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Lead
4.374 µg/L 29%
of the EPA limit 15 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2018
1/1 SYR4
Trichloroacetic Acid
4.0795 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Bromodichloromethane
2.2624999999999997 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Chromium
1.9105 µg/L 1.9%
of the EPA limit 100 µg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2017
1/1 SYR4
Dibromoacetic Acid
1.238 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Dibromochloromethane
0.6400 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Bromoform
0.5400 µg/L
No EPA limit set
Main supplier: ST CHARLES PWS · 78,961 people · 2019
1/1 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: ST CHARLES PWS · 78,961 people · 2024
1/1 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 St. Charles

SupplierPopulation served
ST CHARLES PWS 78,961

Frequently asked questions about St. Charles tap water

Is St. Charles tap water safe to drink?

EPA testing detected 19 contaminants in the water serving St. Charles. 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 St. Charles?

1 public water supplier report drinking-water monitoring for St. Charles, Missouri to the EPA. Each is listed above with its population served.

What contaminants are in St. Charles's water?

The contaminants EPA monitoring detected in St. Charles include Fluoride, Barium, Lithium, Total Haloacetic Acids (HAA5), Dichloroacetic Acid. 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.