State profile · EPA SDWIS + UCMR5
Wyoming Drinking Water Quality
766 SDWIS-listed systems serve 639,288 people. UCMR5 PFAS detection is 9.1% on the tested subset (lower-third UCMR5 detection (≤ 17.5%)); SDWIS violation rate is 94.5%.
- 766
- SDWIS water systems
- 32,465
- Total violations
- 94.5%
- SDWIS systems w/ a violation
- 9.1%
- UCMR5 PFAS rate (33 tested)
The verdict
UCMR5 PFAS detection is 9.1% (3 of 33 tested) - lower-third UCMR5 detection (≤ 17.5%). According to EPA SDWIS population served, Wyoming ranks #52 of 66 states and territories by people served through public water systems.
- #52 of 66
- Population · states corpus
- 32,465
- Total EPA violations on record
- 12%
- Health-based (MCL / treatment)
- 94.5%
- SDWIS systems with ≥1 violation
SDWIS violation % and UCMR5 PFAS % use different denominators (full inventory vs tested subset). Population ordinal uses SDWIS population served.
Wyoming standing, mid SDWIS violation-rate third
Wyoming lands in the middle third by violation rate (94.5%) - enough flagged systems for peer comparisons without matching the densest ledgers. Population served is smaller (639,288; smaller served population (≤ 1,083,630)), so a high rate can still mean a compact household footprint. Health-based share is 12% - a material slice is exposure-relevant, with the rest monitoring or reporting. UCMR5 PFAS detection is 9.1% 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
Health-based share of this violation record
EPA SDWIS classifications for Wyoming's 32,465 recorded violations.
Wyoming 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.
- WY
Wyoming
94.5 % of systems
- AR
Arkansas
94.5 % of systems
- NY
New York
94.4 % of systems
- 05
EPA Region 5 — Tribal Water Systems
94.7 % of systems
- MT
Montana
94.7 % of systems
What this shows Wyoming's rate is 94.5% (724 of 766 systems; middle-third rate (≤ 96.1%)). This is a comparison of recorded SDWIS violations, not a measure of current water safety.
Wyoming vs all jurisdictions by SDWIS system inventory
Where this state's public water system count sits among every state and territory on PlainWater
766 41st of 66 higher than 25 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 Wyoming
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.