PlainWater

St. Mary Parish, Louisiana

SDWIS compliance plate

Sheet LA101 · St. Mary Parish 16 sys · 1,325 viol · #806/3254

VIOL-SEVERE · HEALTH-HIGH · RANK-UPPER · PHOTO-FINISH · PFAS-HIGH · SRC-SW · SYS-SMALL · BOOK-FULL

  • VIOL-SEVERE 100.0% flagged
  • HEALTH-HIGH 57.4% health
  • RANK-UPPER #806/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-HIGH 85.7% detect
  • SRC-SW SW lead 56%
  • SYS-SMALL 16 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Jefferson Parish (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, St. Mary Parish ranks #806 of 3,254 counties by people served, and #20 of 64 counties in Louisiana. See methodology · corpus placement.

St. Mary Parish standing, mid-flagged corpus third

Flagged-system rate 100.0% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 57.4% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 85.7% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #806 of 3,254 · #20 of 64 in Louisiana.

Flagged-rate neighbourhood around St. Mary Parish

Lowest/highest poles plus in-state counties nearest St. Mary Parish on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% St. Tammany Pa · lowest Jefferson Pari · near Terrebonne Par · near 78.9% 100% 100% 100% 100% 100% 100%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

Compare beyond Louisiana

Mid-flagged peers for St. Mary Parish

Cross-state counties nearest St. Mary Parish on flagged-system share (100.0%) and cumulative violation count (1,325). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

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.