Illinois
DeKalb County drinking water quality
57 active public water systems serve 95,710 people in DeKalb County. 32 are compliant, 25 had at least one EPA violation in the past three years, 2 are designated serious violators, and 1 carries a health flag.
Needs attention
Community water systems
20 systems, largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Dekalb De Kalb |
40,290 | 1 | 0 | |
|
Sycamore Sycamore |
18,500 | 2 | 0 | |
|
Sandwich Sandwich |
7,156 | 2 | 0 | |
|
Northern Illinois University-Dekalb |
6,500 | 0 | 0 | |
|
Genoa Genoa |
5,298 | 3 | 0 | |
|
Cortland Cortland |
4,398 | 1 | 0 | |
|
Hinckley Hinckley |
2,006 | 0 | 0 | |
|
Somonauk Somonauk |
1,860 | 0 | 0 | |
|
Kirkland Kirkland |
1,650 | 0 | 0 | |
|
Waterman Waterman |
1,497 | 0 | 0 | |
|
Kingston Kingston |
1,160 | 0 | 0 | |
|
Malta Malta |
1,143 | 3 | 0 | |
|
Suburban Apartments (de Kalb Univ Dvl) |
1,050 | 5 | 1 | |
|
Shabbona Shabbona |
913 | 2 | 0 | |
|
Cortland Corners MHP |
205 | 10 | 3 | |
|
Buck Lake Estates Subdivision |
150 | 0 | 0 | |
|
Triangle Manufactured Home Community Sandwich |
124 | 0 | 0 | |
|
Valley View Subdivision (dekalb) |
120 | 2 | 1 | |
|
Sandwich Estates MHP Sandwich |
90 | 0 | 0 | |
|
Donny Brook Estates Subdivision |
30 | 2 | 0 |
Non-community systems (37: schools, campgrounds, workplaces, restaurants)
These systems serve places people visit rather than homes.
Inactive systems (196, no longer operating or reporting)
Kept for the record and excluded from the county totals above. Browse inactive systems.
About this data
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Illinois records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.