States/IL

Sewer overflows in Illinois

Sewer overflow record — reported spills, the worst utilities, and how often overflows reached waterways in Illinois.

Reported events
1,356
Total volume
3.6B gal
Reached waterways
1(0%)
Latest event
Jun 22, 2026

Worst utilities in Illinois

Ranked by number of reported overflow events.

#UtilityEventsVolumeReached water
1PEKIN STP #1 SSCS99116.3M gal0
2MARION WRF, CITY OF SSCS794.9M gal0
3WOOD RIVER, CITY OF SSCS60132.9M gal0
4FOUR RIVERS SANITATION AUTHORITY STP SSCS57120K gal0
5LAWRENCEVILLE STP, CITY OF SSCS496.2M gal0
6BELLEVILLE STP #1, CITY OF SSCS442.9B gal0
7CARLINVILLE STP SSCS3646.4M gal0
8GRANITE CITY WWTP, CITY OF SSCS369.4M gal0
9SANGAMON COUNTY WATER RECLAMATION DISTRICT SSCS311.3M gal0
10DUQUOIN STP, CITY OF SSCS31267K gal0
11ALTON STP, CITY OF SSCS277.8M gal0
12ILLINOIS AMERICAN WATER - JERSEYVILLE STP SSCS2216.8M gal0
13LEBANON STP, CITY OF201.5M gal0
14ILLINOIS AMERICAN WATER - ROSICLARE WWTP SSCS20297K gal0
15METROPOLIS STP, CITY OF SSCS1918.9M gal0
16MT. VERNON STP, CITY OF SSCS182K gal0
17SPRING CREEK STP SSCS17113K gal0
18TROY STP, CITY OF SSCS156.9M gal0
19CAMBRIDGE STP, VILLAGE OF SSCS156.5M gal0
20CARMI STP, CITY OF SSCS1425K gal0
21EDDYVILLE STP, VILLAGE OF SSCS143K gal0
22FLAGG CREEK WRD - MCELWAIN STP SSCS134K gal0
23AQUA ILLINOIS - UNIVERSITY PARK WWTF SSCS13124K gal0
24CHESTER STP SSCS13105K gal0
25PINCKNEYVILLE, CITY OF SSCS1213.4M gal0
26MOUNT CARMEL STP, CITY OF SSCS12429K gal0
27AURORA, CITY OF SSCS12963 gal0
28KISHWAUKEE WATER RECLAMATION DISTRICT WWTP SSCS102.1M gal0
29MASCOUTAH STP, CITY OF SSCS101.9M gal0
30OKAWVILLE STP, VILLAGE OF SSCS101.1M gal0

Biggest spills in Illinois

The largest single reported overflow events.