EPA UCMR5 · 2023→2024
PFAS Detection-Rate Change Rankings
Year-over-year change in the share of public water systems with at least one PFAS detection, limited to systems sampled in both 2023 and 2024. Floor: ≥20 dual-year systems per state. Raw detection counts are not used: UCMR5 rollout added many newly tested systems.
- +10.34 pp
- Largest rise · Minnesota
- -22.5 pp
- Largest decline · Pennsylvania
- 29
- States with ≥20 dual-year systems
Minnesota posted the largest PFAS detection-rate increase among 29 states with ≥20 systems sampled in both 2023 and 2024: +10.34 pp (65.52% → 75.86%).
2023→2024 PFAS detection-rate change
Minnesota leads this board at +10.34 pp (65.52% → 75.86%). The 5th-place cutoff to appear on the rising list is +1.39 pp; Pennsylvania sits at the other end at -22.5 pp.
- +10.34 pp
- #1 rise · Minnesota
- +1.39 pp
- #5 cutoff, rising board
- -22.5 pp
- Largest decline · Pennsylvania
- 29
- States with ≥20 dual-year systems
Detection rate = share of like-for-like systems with ≥1 PFAS detection in that calendar year of UCMR5 sampling. Not a drinking-water safety score and not a violation rate (see /rankings/pfas-detection for the cumulative UCMR5 snapshot).
Largest PFAS detection-rate increases (2023→2024)
5 steepest increases
| # | State | YoY | Rate |
|---|---|---|---|
| 1 | Minnesota 29 dual-year systems | +10.34 pp | 65.52%→75.86% |
| 2 | Indiana 32 dual-year systems | +6.25 pp | 21.88%→28.13% |
| 3 | Washington 51 dual-year systems | +5.88 pp | 23.53%→29.41% |
| 4 | Mississippi 30 dual-year systems | +3.33 pp | 0%→3.33% |
| 5 | Illinois 72 dual-year systems | +1.39 pp | 33.33%→34.72% |
23 steepest declines
| # | State | YoY | Rate |
|---|---|---|---|
| 1 | Pennsylvania 40 dual-year systems | -22.5 pp | 42.5%→20% |
| 2 | Kentucky 41 dual-year systems | -21.95 pp | 43.9%→21.95% |
| 3 | Virginia 34 dual-year systems | -20.59 pp | 41.18%→20.59% |
| 4 | Tennessee 60 dual-year systems | -16.67 pp | 36.67%→20% |
| 5 | Georgia 46 dual-year systems | -15.22 pp | 47.83%→32.61% |
| 6 | Utah 27 dual-year systems | -14.81 pp | 25.93%→11.11% |
| 7 | Texas 247 dual-year systems | -12.55 pp | 67.21%→54.66% |
| 8 | Louisiana 44 dual-year systems | -11.36 pp | 31.82%→20.45% |
| 9 | Wisconsin 27 dual-year systems | -11.11 pp | 33.33%→22.22% |
| 10 | North Carolina 67 dual-year systems | -10.45 pp | 58.21%→47.76% |
| 11 | New York 53 dual-year systems | -9.43 pp | 32.08%→22.64% |
| 12 | Michigan 53 dual-year systems | -7.55 pp | 9.43%→1.89% |
| 13 | Oklahoma 29 dual-year systems | -6.9 pp | 44.83%→37.93% |
| 14 | Massachusetts 45 dual-year systems | -6.67 pp | 60%→53.33% |
| 15 | New Jersey 65 dual-year systems | -6.15 pp | 64.62%→58.46% |
| 16 | Colorado 38 dual-year systems | -5.26 pp | 18.42%→13.16% |
| 17 | South Carolina 39 dual-year systems | -5.13 pp | 58.97%→53.85% |
| 18 | Puerto Rico 24 dual-year systems | -4.17 pp | 41.67%→37.5% |
| 19 | Oregon 27 dual-year systems | -3.7 pp | 11.11%→7.41% |
| 20 | Arizona 36 dual-year systems | -2.78 pp | 38.89%→36.11% |
| 21 | Alabama 44 dual-year systems | -2.27 pp | 40.91%→38.64% |
| 22 | Florida 81 dual-year systems | -1.23 pp | 54.32%→53.09% |
| 23 | California 205 dual-year systems | -0.49 pp | 34.15%→33.66% |
The cumulative UCMR5 snapshot (all tested systems, not limited to dual-year pairs) still lives on PFAS detection by state. Source: EPA UCMR5 sample results joined to SDWIS public water systems.
Download the SDWIS/UCMR5 state landscape snapshot cited on this page: sdwis-state-landscape.csv (same CSV as /statistics, CC0).
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 UCMR5 sample results; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15.