PlainWater

Jefferson County, Illinois

SDWIS compliance plate

Sheet IL081 · Jefferson County 16 sys · 279 viol · #1252/3254

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

  • VIOL-SEVERE 68.8% flagged
  • HEALTH-LOW 4.3% health
  • RANK-UPPER #1252/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-HIGH 100.0% detect
  • SRC-SW SW lead 94%
  • SYS-SMALL 16 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Ford County (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Jefferson County ranks #1,252 of 3,254 counties by people served, and #41 of 102 counties in Illinois. See methodology · corpus placement.

Jefferson County standing, lower-flagged corpus third

Flagged-system rate 68.8% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 4.3% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 100.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #1,252 of 3,254 · #41 of 102 in Illinois.

Flagged-rate neighbourhood around Jefferson County

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

0% 20% 40% 60% 80% 100% Sangamon · lowest Ford · near Perry · near Pulaski · highest 58.8% 68.8% 68.8% 69.1% 70% 70.4% 100%

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

Water Systems

System Name Population Violations PFAS
Mount Vernon 15,793 39 Detected
Northeast Mount Vernon Water Company 5,483 23 Detected
Woodlawn 3,587 31 Detected
Dix-Kell Water Commssion 1,972 22 -
Belle Rive 1,930 36 -
Waltonville 1,901 21 -
Bluford 1,880 58 -
Bonnie 437 22 -
Oak Grove Village 362 1 -
Rolling Meadows Mhc (Jefferson Co) 218 0 -
Moores Prairie Township Water Company 213 0 -
Nason 207 22 -
Wal-Mart Supercenter 0224 25 0 -
Icehouse South Mt Vernon 25 0 -
Icehouse Main Mt Vernon 25 0 -
Lucky Ice USA LLC - Mt Vernon 25 4 -

Compare beyond Illinois

Lower-flagged peers for Jefferson County

Cross-state counties nearest Jefferson County on flagged-system share (68.8%) and cumulative violation count (279). 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.