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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
1–25 of 152Sioux Falls
SD4600294 · 216,462 served
Rapid City
SD4600406 · 72,009 served
Aberdeen
SD4600020 · 27,989 served
Brookings Municipal Utilities
SD4600071 · 23,377 served
Watertown Municipal Utilities
SD4600356 · 23,230 served
Web Water Development Association
SD4601089 · 20,750 served
Mitchell
SD4600214 · 15,651 served
Yankton
SD4600423 · 15,411 served
Huron
SD4600169 · 14,263 served
Pierre
SD4600242 · 14,091 served
Box Elder
SD4600046 · 14,000 served
Minnehaha Community Water Corp
SD4600432 · 13,435 served
By Water District
SD4600865 · 13,320 served
Spearfish
SD4600311 · 12,193 served
Mid-dakota Rural Water
SD4602175 · 11,833 served
Vermillion
SD4600342 · 11,695 served
Rapid Valley Sanitary District
SD4600274 · 11,408 served
Brandon
SD4600048 · 11,048 served
Harrisburg
SD4600148 · 10,297 served
Ellsworth Afb
SD4680004 · 9,100 served
Tea
SD4600409 · 7,381 served
Sturgis
SD4600321 · 7,020 served
Kingbrook I Rural Water System
SD4600431 · 6,455 served
Randall Community Water District
SD4600433 · 6,248 served
Brookings-deuel Rural Water System
SD4600430 · 6,200 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