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Tap water quality report

Williamstown, MO

EPA monitoring detected 16 contaminants across the 1 water supplier serving Williamstown. 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
7,140
people served
16
contaminants found
Missouri rankings Lead in Missouri PFAS in Missouri

What was found in Williamstown'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
Nitrate-Nitrite
6779 µg/L 68%
of the EPA limit 10000 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Copper
642.4 µg/L 49%
of the EPA limit 1300 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2017
1/1 SYR4
Fluoride
130 µg/L 3.3%
of the EPA limit 4000 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2017
1/1 SYR4
Barium
54.07 µg/L 2.7%
of the EPA limit 2000 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2017
1/1 SYR4
TTHM
9.848 µg/L 12%
of the EPA limit 80 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Monobromoacetic Acid
4.7095 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Lead
4.015 µg/L 27%
of the EPA limit 15 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2017
1/1 SYR4
Dibromochloromethane
3.266 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Bromodichloromethane
3.244 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Chromium
3.0075 µg/L 3%
of the EPA limit 100 µg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2017
1/1 SYR4
Dichloroacetic Acid
2.9175 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Trichloroacetic Acid
2.774 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Chloroform
2.5 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Dibromoacetic Acid
1.364 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Bromoform
0.7725 µg/L
No EPA limit set
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2019
1/1 SYR4
Lead
0.0022 mg/L 15%
of the EPA limit 0.0150 mg/L
Main supplier: CLARK COUNTY CONS PWSD 1 · 7,140 people · 2023
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 Williamstown

SupplierPopulation served
CLARK COUNTY CONS PWSD 1 7,140

Frequently asked questions about Williamstown tap water

Is Williamstown tap water safe to drink?

EPA testing detected 16 contaminants in the water serving Williamstown. 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 Williamstown?

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

What contaminants are in Williamstown's water?

The contaminants EPA monitoring detected in Williamstown include Nitrate-Nitrite, Copper, Fluoride, Barium, 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.