Illinois
Illinois sits in the Midwest and draws its water primarily from Lake Michigan, Mississippi River, and deep aquifers. With roughly 12.6 million residents, the state has minimal formal water reuse to date, reusing an estimated 5% of its treated wastewater.
Illinoiswater quality & safety
Top violation drivers in Illinois
| Contaminant / rule | Systems |
|---|---|
| LEAD AND COPPER RULE REVISIONS | 146 |
| Lead and Copper Rule | 96 |
| TTHM | 59 |
| Interim Enhanced Surface Water Treatment Rule | 38 |
| Combined Radium (-226 and -228) | 31 |
| Arsenic | 28 |
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1 · health-based violations since 2016
Lake Michigan provides Chicago abundant supply, but suburban communities pumping deep aquifers face declining levels.
On the U.S. Drought Monitor scale, Illinois currently tracks around abnormally dry to moderate conditions. Illinois has 1,785 community water systems serving about 12 million people; EPA records show 420 of them (23.5%) with a health-based Safe Drinking Water Act violation since 2016. The pages below break down the water issues that matter most here and the communities working on solutions.
Drought history — severe+ extent
% of Illinois in severe drought or worse (D2+) each late summer.
Source: U.S. Drought Monitor (NDMC/UNL, USDA, NOAA) · latest 2026-06-09
Water use (USGS 2015)
- Per-capita (public supply)
- 126 gpcd
- Total withdrawals
- 10.5 Bgal/d
- From groundwater
- 8.3%
- Irrigation share
- 2.2%
- Wastewater reused (est.)
- ~5%
Primary water sources
- ≈ Lake Michigan
- ≈ Mississippi River
- ≈ deep aquifers
Common questions
Is tap water safe in Illinois?
Illinois has 1,785 community water systems serving about 12 million people. EPA records show 420 of them (23.5%) with at least one health-based Safe Drinking Water Act violation since 2016, and 29 system(s) over the federal lead action level. Most large systems meet standards; check your specific city and your utility's annual report.
What contaminants are most common in Illinois's water?
The most frequent health-based violations involve LEAD AND COPPER RULE REVISIONS, Lead and Copper Rule, TTHM.
How much water does Illinois use per person?
Public water systems in Illinois withdraw about 126 gallons per person per day (USGS 2015), drawing 8.3% of fresh water from groundwater.
How bad is the drought in Illinois?
As of 2026-06-09, 19.8% of Illinois is in drought (D1+) and 0% is in severe drought or worse, per the U.S. Drought Monitor.
Cities in Illinois
30 trackedChicago
Chicago, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Aurora
Aurora, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Rockford
Rockford, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Joliet
Joliet, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Naperville
Naperville, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Springfield
Springfield, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Peoria
Peoria, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
North Peoria
North Peoria, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Elgin
Elgin, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Waukegan
Waukegan, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
West Town
West Town, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Champaign
Champaign, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
Key issues in Illinois
Aging Infrastructure
Much of America's water infrastructure is decades past its design life, leaking trillions of gallons a year and demanding hundreds of billions in reinvestment.
ExploreGroundwater Depletion
Aquifers from the Central Valley to the Ogallala are being pumped faster than they recharge, causing land subsidence and threatening long-term supply.
Explore