State profile · EPA SDWIS + UCMR5
Puerto Rico Drinking Water Quality
458 SDWIS-listed systems serve 3,328,141 people. UCMR5 PFAS detection is 38.4% on the tested subset (upper-third UCMR5 detection (> 35.3%)); SDWIS violation rate is 99.6%.
- 458
- SDWIS water systems
- 164,144
- Total violations
- 99.6%
- SDWIS systems w/ a violation
- 38.4%
- UCMR5 PFAS rate (99 tested)
The verdict
UCMR5 PFAS detection is 38.4% (38 of 99 tested) - upper-third UCMR5 detection (> 35.3%). According to EPA SDWIS population served, Puerto Rico ranks #31 of 66 states and territories by people served through public water systems.
- #31 of 66
- Population · states corpus
- 164,144
- Total EPA violations on record
- 21%
- Health-based (MCL / treatment)
- 99.6%
- SDWIS systems with ≥1 violation
SDWIS violation % and UCMR5 PFAS % use different denominators (full inventory vs tested subset). Population ordinal uses SDWIS population served.
Puerto Rico standing, high SDWIS violation-rate third
Puerto Rico sits in the upper third of jurisdictions by SDWIS violation rate (99.6%), so the system lists below sample one of the denser state-level compliance trails in this extract. Population served is mid-pack at 3,328,141 (mid served population (≤ 5,131,439)). Health-based share is 21% - a material slice is exposure-relevant, with the rest monitoring or reporting. UCMR5 PFAS detection is 38.4% on the tested subset (upper-third UCMR5 detection (> 35.3%)) - 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 Puerto Rico's 164,144 recorded violations.
Puerto Rico 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.
- PR
Puerto Rico
99.6 % of systems
- WV
West Virginia
99.5 % of systems
- DC
District of Columbia
100 % of systems
- 01
EPA Region 1 — Tribal Water Systems
100 % of systems
- 02
EPA Region 2 — Tribal Water Systems
100 % of systems
What this shows Puerto Rico's rate is 99.6% (456 of 458 systems; upper-third rate (> 96.1%)). This is a comparison of recorded SDWIS violations, not a measure of current water safety.
Puerto Rico vs all jurisdictions by SDWIS system inventory
Where this state's public water system count sits among every state and territory on PlainWater
458 48th of 66 higher than 18 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 Puerto Rico
Showing top 30 of 72 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.