Tap WaterIndex

← South Dakota

Tap water quality report

St Onge, SD

EPA monitoring detected 10 contaminants across the 1 water supplier serving St Onge. A detection doesn't automatically mean the water is unsafe — see the highest level found for each below, with its EPA source and period.

1
water supplier
255
people served
10
contaminants found
South Dakota rankings Lead in South Dakota PFAS in South Dakota

What was found in St Onge's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
1980 µg/L 20%
of the EPA limit 10000 µg/L
 1/1 SYR4
Fluoride
500 µg/L 13%
of the EPA limit 4000 µg/L
 1/1 SYR4
Copper
483 µg/L 37%
of the EPA limit 1300 µg/L
 1/1 SYR4
TTHM
6.31 µg/L 7.9%
of the EPA limit 80 µg/L
 1/1 SYR4
Lead
6 µg/L 40%
of the EPA limit 15 µg/L
 1/1 SYR4
Selenium
6 µg/L 12%
of the EPA limit 50 µg/L
 1/1 SYR4
Gross Alpha, Excl. Radon And U
5.48 pCi/L 37%
of the EPA limit 15 pCi/L
 1/1 SYR4
Arsenic
5 µg/L 50%
of the EPA limit 10 µg/L
 1/1 SYR4
Total Haloacetic Acids (HAA5)
1.5 µg/L 2.5%
of the EPA limit 60 µg/L
 1/1 SYR4
Lead
0.0020 mg/L 13%
of the EPA limit 0.0150 mg/L
 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 single worst sample on record — 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 Onge

SupplierPopulation served
SAINT ONGE SEWER & WATER CO 255

Frequently asked questions about St Onge tap water

Is St Onge tap water safe to drink?

EPA testing detected 10 contaminants in the water serving St Onge. 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 Onge?

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

What contaminants are in St Onge's water?

The contaminants EPA monitoring detected in St Onge include Nitrate, Fluoride, Copper, TTHM, Lead. The full list, with the highest level found 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.