State profile · EPA SDWIS + UCMR5
South Dakota Drinking Water Quality
654 SDWIS-listed systems serve 915,901 people. UCMR5 PFAS detection is 14.3% on the tested subset (lower-third UCMR5 detection (≤ 17.5%)); SDWIS violation rate is 91.6%.
- 654
- SDWIS water systems
- 56,254
- Total violations
- 91.6%
- SDWIS systems w/ a violation
- 14.3%
- UCMR5 PFAS rate (49 tested)
The verdict
UCMR5 PFAS detection is 14.3% (7 of 49 tested) - lower-third UCMR5 detection (≤ 17.5%). According to EPA SDWIS population served, South Dakota ranks #47 of 66 states and territories by people served through public water systems.
- #47 of 66
- Population · states corpus
- 56,254
- Total EPA violations on record
- 15%
- Health-based (MCL / treatment)
- 91.6%
- SDWIS systems with ≥1 violation
SDWIS violation % and UCMR5 PFAS % use different denominators (full inventory vs tested subset). Population ordinal uses SDWIS population served.
South Dakota standing, low SDWIS violation-rate third
South Dakota is in the lower third of jurisdictions by violation rate (91.6%; lower-third rate (≤ 92.5%)). That is a relative placement among peers, not a claim that most systems are clean - 599 of 654 still carry ≥1 record. Population served is smaller (915,901; smaller served population (≤ 1,083,630)), so a high rate can still mean a compact household footprint. Health-based share is 15% - a material slice is exposure-relevant, with the rest monitoring or reporting. UCMR5 PFAS detection is 14.3% on the tested subset (lower-third UCMR5 detection (≤ 17.5%)) - a different denominator from the SDWIS violation rate. Systems listed below are ranked by population served or violation count; pair rate with inventory size before reading exposure scale.
Nationwide similar states
Nearest by SDWIS violation rate
Nearest by population served
Health-based share of this violation record
EPA SDWIS classifications for South Dakota's 56,254 recorded violations.
South Dakota vs nearest violation-rate peers
Share of SDWIS-listed systems with at least one recorded violation; peers are nearest by absolute rate distance, not a fixed top-seven list.
- SD
South Dakota
91.6 % of systems
- GA
Georgia
92.1 % of systems
- WA
Washington
92.1 % of systems
- LA
Louisiana
92.5 % of systems
- NV
Nevada
92.5 % of systems
What this shows South Dakota's rate is 91.6% (599 of 654 systems; lower-third rate (≤ 92.5%)). This is a comparison of recorded SDWIS violations, not a measure of current water safety.
South Dakota vs all jurisdictions by SDWIS system inventory
Where this state's public water system count sits among every state and territory on PlainWater
654 43rd of 66 higher than 23 of 66 jurisdictions
States and territories, banded by SDWIS-listed public water system count
Each bar is a band; taller bars hold more jurisdictions. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS state aggregates · 2026-05-15
Largest Water Systems
Most Violations
Counties in South Dakota
Showing top 30 of 65 counties.
Context: PFAS in drinking water · methodology · all states
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.