Joliet
Joliet, IL water profile — supply sources, drought status, wastewater reuse, and the key water issues facing the city.
joliet
groundwater (wells) · local government · PWSID IL1970450
Below EPA's 15 ppb lead action level at last testing.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Joliet is a mid-sized city and the 4th-largest in Illinois, home to roughly 147,861 residents. Joliet's drinking water comes largely from the same regional sources that serve Illinois: Lake Michigan, Mississippi River, and deep aquifers.
As elsewhere in Illinois, the central challenge is aging infrastructure. Lake Michigan provides Chicago abundant supply, but suburban communities pumping deep aquifers face declining levels.
Illinois reuses an estimated 5% of its treated wastewater and maintains minimal reuse programs; Joliet tracks abnormally dry to moderate drought conditions on the U.S. Drought Monitor scale.
Explore the Illinois profile for statewide context, or dig into the water issues shaping Joliet below.
Will County water quality
Source: EPA SDWIS · 2026 Q1
At a glance
- Population ~147,861 (4th-largest in Illinois)
- Primary sources: Lake Michigan, Mississippi River, and deep aquifers
- Drought: abnormally dry to moderate conditions
- State reuse rate: ~5% of wastewater
Statewide drought history
% of Illinois in severe+ drought (Moderate (D1) now).
Source: U.S. Drought Monitor
Common questions
Is tap water safe in Joliet?
Joliet's largest water system, JOLIET, serves about 160,000 people. EPA records show 1 health-based violation(s) since 2016 and a most-recent 90th-percentile lead level of 0 ppb (EPA action level is 15 ppb). Always check your own provider's annual Consumer Confidence Report.
Where does Joliet get its water?
JOLIET draws primarily from groundwater (wells), part of Illinois's supply from Lake Michigan, Mississippi River, deep aquifers.
Related water issues
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