PWSID
SD4600406
State
South Dakota
City
RAPID CITY
Population served
72,009
Primary source
Surface water
Score history
▼ 1 point — the score moved from 100 to 99 on Jun 18, 2026, as newly published EPA data was incorporated.
2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.
PFAS & contaminant readings
Latest detections from EPA’s UCMR5 monitoring (through Jun 2025). Levels in parts per trillion (ppt).
PFHxS
Perfluorohexanesulfonic acid
5.6 ppt
limit 10 ppt
Violations & enforcement
3
Violations on record
0
Unaddressed
0
Health-based
10
Enforcement actions
From EPA ECHO (SDWIS), most recent enforcement Jun 2003. Official EPA record →
Recent enforcement actions
- State action · SIF Jun 2003
- State action · SIF Jun 2003
- State action · SIF Jun 2003
- State action · SOX Feb 2003
- State action · SOX Feb 2003
- State action · SOX Feb 2003
- State action · SIE Feb 2003
- State action · SIE Feb 2003
Area water-quality monitoring
Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.
Copper
4 stations · latest May 2020
Lead
4 stations · latest May 2020
Arsenic
4 stations · latest May 2020
Nitrate
3 stations · latest Jun 2021
Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.
This profile is built from EPA public records for system SD4600406 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.