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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
151–152 of 152Key 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.
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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