St. Clair County, Illinois
SDWIS compliance plate
Sheet IL163 · St. Clair County 54 sys · 3,100 viol · #271/3254
VIOL-SEVERE · HEALTH-LOW · RANK-TOP · PHOTO-FINISH · PFAS-HIGH · SRC-SW · SYS-MID · BOOK-FULL
- VIOL-SEVERE 61.1% flagged
- HEALTH-LOW 9.6% health
- RANK-TOP #271/3254
- PHOTO-FINISH ±0.7 pp
- PFAS-HIGH 80.0% detect
- SRC-SW SW lead 67%
- SYS-MID 54 systems
- BOOK-FULL 7/7 fields
Nearest flagged-rate peer: DuPage County ( -0.7 pp flagged-rate)
According to EPA SDWIS county population served used on /counties, St. Clair County ranks #271 of 3,254 counties by people served, and #8 of 102 counties in Illinois. See methodology · corpus placement.
St. Clair County standing, lower-flagged corpus third
Flagged-system rate 61.1% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 9.6% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 80.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #271 of 3,254 · #8 of 102 in Illinois.
Flagged-rate neighbourhood around St. Clair County
Lowest/highest poles plus in-state counties nearest St. Clair County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.
Water Systems
Compare beyond Illinois
Lower-flagged peers for St. Clair County
Cross-state counties nearest St. Clair County on flagged-system share (61.1%) and cumulative violation count (3,100). 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.
Similar violation load
Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).
Read our methodology · Check your water system - how this data is sourced, computed, and verified.
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.