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South Dakota Water Quality
152
Utilities in database
0.8M
Residents served
45%
On private wells
2
Key contaminants tracked
Drinking Water in South Dakota
South Dakota has 152 community water systems serving approximately 0.8 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, arsenic. 45% of South Dakota residents rely on private wells. DENR holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in South Dakota
26–50 of 152Madison
SD4600199 · 6,191 served
Lincoln County Rural Water System
SD4600304 · 5,965 served
Big Sioux Community Water System
SD4600429 · 5,800 served
Brown-day-marshall Rws
SD4600882 · 5,673 served
Belle Fourche
SD4600037 · 5,617 served
South Lincoln Rural Water System
SD4600870 · 5,250 served
Grant-roberts Rural Water System
SD4600864 · 5,050 served
Tripp County Water User District
SD4600520 · 4,860 served
Clay Rural Water System
SD4600626 · 4,780 served
Wr/lj - Mni Wiconi
SD4602223 · 4,720 served
Black Hawk Water User District
SD4600043 · 4,500 served
Sioux Rural Water System
SD4600866 · 4,280 served
Tm Rural Water District
SD4600999 · 4,250 served
Eagle Butte
SD4600010 · 4,000 served
Dakota Dunes Cid
SD4602093 · 3,700 served
Dell Rapids
SD4600105 · 3,633 served
Davison Rural Water System Inc
SD4601090 · 3,485 served
Hartford
SD4600150 · 3,396 served
Hot Springs
SD4600163 · 3,395 served
Mobridge
SD4600215 · 3,261 served
Milbank
SD4600207 · 3,200 served
Canton
SD4600082 · 3,066 served
North Sioux City
SD4600226 · 3,042 served
Lead
SD4602164 · 2,982 served
Winner
SD4600373 · 2,921 served
Key Contaminant Concerns in South Dakota
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Arsenic
Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.
South Dakota Water FAQs
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Data source: Utility data from EPA SDWIS. 152 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-24