South Dakota Tap Water Quality
Check a South Dakota ZIP Code
Overview
Sioux Falls blends Big Sioux aquifer wells with Missouri River water from the Lewis & Clark regional pipeline, a multi-state project that has transformed supply reliability across the region; Rapid City draws clean Black Hills sources. Both comply fully.
Rural South Dakota mirrors its neighbors: naturally mineral-heavy prairie groundwater (iron, sulfates, TDS) pushed the state into regional rural water systems, agricultural nitrate pressures shallow wells, and scattered arsenic and uranium occurrences track Black Hills geology and legacy mining at Edgemont.
Common Contaminants in South Dakota
Shallow ag-area wells and a few small systems exceed limits after wet cycles
Natural prairie groundwater character: the driver for regional pipeline supply rather than a health violation
Localized Black Hills-area occurrences in wells; testing recommended
Violations & Compliance
Compliance is solid, strengthened as Lewis & Clark pipeline water replaces marginal local wells; remaining violations are small-system nitrate and monitoring lapses.
Water Hardness in South Dakota
Very hard, typically 200–400 mg/L. Missouri River and glacial groundwater make South Dakota water very hard statewide; many systems soften at the plant.
Hardness affects taste, limescale, and soap — not safety. Compare levels across all cities or read the water hardness guide.
City Reports for South Dakota
We haven't published individual city water reports for South Dakota yet. Use the ZIP lookup for a statewide assessment, and check your utility's annual Consumer Confidence Report for local detail.
Frequently Asked Questions
Sources & References
The safety rating and guidance on this page draw on the following sources. See our full methodology.
- •US EPA Safe Drinking Water Act regulations
- •EWG Tap Water Database
- •The utility's most recent Consumer Confidence Report (CCR)
- •WHO Guidelines for Drinking-water Quality