Illinois Water Quality Records

Chicago · IL0316000

Lake Michigan and two treatment plants

Chicago’s 2025 report identifies Lake Michigan as its source, with treatment at the Jardine and Sawyer water purification plants. This is system-level source context; it does not identify the plant serving a particular address.

The report includes two individual-filter turbidity monitoring violations and a lead-service-line notification and certification violation. Its later remediation statements belong to the dated notices, rather than a current system status.

Read Chicago’s report overview →

Aurora · IL0894070

Fox River water blended with groundwater

Aurora’s 2025 report describes Fox River surface water blended with shallow and deep wells, including the Cambrian-Ordovician Aquifer system.

Read the lead results and zinc monitoring/reporting notice alongside the other tables. The lead row records sites above the action level while printing N in its violation column; the zinc notice covers 2023–2025. Neither field can stand in for the complete report.

Read Aurora’s report overview →

Rockford · IL2010300

Groundwater and a dated monitoring notice

Rockford’s report covers January through December 2025 and identifies groundwater as its source.

It also includes a notice distributed in June 2026 about missed monitoring during 2023–2025. The City attributes the missed samples to clerical errors and describes later sampling. Those statements do not establish today’s advisory or compliance status.

Read Rockford’s report overview →

Source comparison

A lake, a river-and-well blend, and groundwater

Chicago, Aurora, and Rockford illustrate different sources within Illinois. These three examples describe the selected systems, without providing statewide source shares or identifying the supply to every Illinois home.

Record identity

Use the public water system number

Chicago’s PWSID is IL0316000, Aurora’s is IL0894070, and Rockford’s is IL2010300. Match the system number and provider name to your water bill or provider confirmation before choosing a report.

A city entry point helps you browse. It does not prove an exclusive service area or confirm that your address receives that system’s water.

Review dates

Annual reports and official records have different clocks

These system profiles retain their August 3, 2026 review date. This state guide’s source review was September 13, 2026; that date does not refresh every sample, service-line record, or public notice.

The August review separately recorded a Chicago dinoseb monitoring violation and Aurora lead and zinc record context. Consult the system’s current official record for subsequent actions.

Private wells

Use the private-water and laboratory pathway

Illinois Department of Public Health’s private-water program covers well construction, modification, and sealing outside community water wells. Its page links local health departments and accredited laboratories for well-water testing.

If your home uses a private well, start with your local health department and ask which tests and sampling instructions apply. A nearby municipal report cannot describe your well’s water.

Find Illinois private-well and laboratory resources →

Lead and service lines

Ask about the service line separately

Illinois EPA’s lead-service-line page provides inventory, replacement-plan, and notification resources. An inventory record and a tap sample answer different questions.

Use your provider’s inventory and contact route to ask about a particular service line or testing. State guidance alone does not identify pipe material at a home.

Read Illinois lead-service-line information →

Notices and PFAS

Check what kind of notice you are reading

Illinois EPA’s groundwater notices page includes right-to-know and PFAS materials. It is a groundwater-contamination notice resource, rather than a complete list of current drinking-water advisories.

For an instruction affecting your water use, check the provider’s current notice and its affected area, issue date, and instructions. The annual-report notices above remain historical.

Read Illinois groundwater contamination notices →

Find the public-water program →