PlainWater

Monroe County, Illinois

SDWIS compliance plate

Sheet IL133 · Monroe County 17 sys · 733 viol · #1462/3254

VIOL-SEVERE · HEALTH-MID · RANK-MID · ABOVE-PEER · PFAS-HIGH · SRC-GW · SYS-SMALL · BOOK-FULL

  • VIOL-SEVERE 64.7% flagged
  • HEALTH-MID 20.3% health
  • RANK-MID #1462/3254
  • ABOVE-PEER +3.6 pp
  • PFAS-HIGH 50.0% detect
  • SRC-GW GW lead 76%
  • SYS-SMALL 17 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: St. Clair County ( -3.6 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Monroe County ranks #1,462 of 3,254 counties by people served, and #48 of 102 counties in Illinois. See methodology · corpus placement.

Monroe County standing, lower-flagged corpus third

Flagged-system rate 64.7% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 20.3% is health-based share in the middle third (≤ 24.5%) . UCMR5 detect rate 50.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #1,462 of 3,254 · #48 of 102 in Illinois.

Flagged-rate neighbourhood around Monroe County

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

0% 20% 40% 60% 80% 100% Sangamon · lowest St. Clair · near Jefferson · near Pulaski · highest 58.8% 60.4% 61.1% 64.7% 68.8% 68.8% 100%

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

Water Systems

System Name Population Violations PFAS
Columbia 11,129 6 Detected
Waterloo 10,190 116 Detected
Fountain Water District 3,650 26 Clean
Valmeyer 1,263 62 Clean
Hecker 429 51 -
Maeystown 340 177 -
Hank and Lillys Fountain Inn LLC 50 0 -
Career Center of Southern Illinois 50 275 -
Waterloo Sportsman Club D Rahn 40 3 -
Ice House Waterloo 40 0 -
Walmart (138339) 25 0 -
Schnucks #242 25 0 -
Schnucks 244 Columbia 25 0 -
Freedom Lake 25 6 -
M & B Ice Columbia 25 0 -
Sugar Spring Ranch Banquet 25 4 -
Midwest Petroleum Co. Ph 66 25 7 -

Compare beyond Illinois

Lower-flagged peers for Monroe County

Cross-state counties nearest Monroe County on flagged-system share (64.7%) and cumulative violation count (733). 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.