Drinking Water Watch
Search by water-system number, name, county, type or primary source.
Open Illinois Drinking Water Watch →Illinois water data
How to Research Illinois Water Quality
Use the exact provider, public-water-system ID, source, sample point, date and report before drawing a conclusion.
Illinois official records
Use Illinois system, report and PFAS sources together
Illinois Drinking Water Watch identifies public systems and monitoring records. Annual Consumer Confidence Reports explain source water and detected contaminants. Illinois EPA’s statewide PFAS investigation evaluated finished drinking-water entry points across community systems, while a household tap still requires property-specific testing when the concern is local plumbing or a private well.
Consumer Confidence Reports
Review the utility’s source, treatment and detected-contaminant information for the reporting year.
Review Illinois CCR guidance →PFAS Investigation
Use statewide entry-point sampling as system-level context without assigning one result to every household.
Review Illinois PFAS records →Quick answer
There is no single statewide tap-water profile.
Illinois includes Lake Michigan, rivers, reservoirs and groundwater surface-water systems, Illinois River systems, reservoir systems, buried-valley aquifers, municipal wells, purchased-water districts and private wells. The correct evidence depends on the address.
Identify the PWSID
Illinois Drinking Water Watch can be searched by system number, name, county, type and primary source. The PWSID keeps similarly named providers from being confused.
Read the annual report
Community systems publish Consumer Confidence Reports describing source water, detected contaminants and compliance information.
Test the tap when needed
Utility-wide data do not describe a private well, service line, fixture, water heater, building plumbing or installed treatment system.
Illinois EPA datasets
PFAS and cyanotoxin records require sample-point context.
The Illinois EPA PFAS service includes PWSID, system, treatment plant, sample point, sample date, analyte, result, unit and raw-versus-finished-water information. The HAB service includes treatment-plant locations and raw- and finished-water cyanotoxin results.
PFAS research checklist
- Confirm the PWSID and treatment plant
- Identify the analyte and unit
- Read the sample date and reporting limit
- Determine whether the point is raw or finished water
- Compare with current utility and EPA records
Cyanotoxin research checklist
- Identify the source-water body
- Separate raw-water and finished-water results
- Use the most recent sample and advisory information
- Do not treat a recreational bloom as a finished tap-water result
- Review the utility's current water-quality page
Source-water regions
Illinois source-water patterns change the questions.
Lake Michigan, rivers, reservoirs and groundwater systems
Review treatment-plant reports, regional supplier relationships and cyanotoxin monitoring. Purchased-water communities may have their own distribution-system PWSID.
Cleveland region →Illinois River systems
Use the exact utility and treatment plant. River monitoring, raw water and finished drinking water are not interchangeable.
Cincinnati region →Buried-valley aquifers
Groundwater systems in southwest and west-central Illinois may use wellfields, source-protection programs and different treatment than surface-water systems.
Illinois regional market →Primary research links
Illinois and federal drinking-water sources
- Illinois Drinking Water Watch
Search official public-water-system records by system number, name, county and source type. - Illinois EPA PFAS sampling service
Illinois treatment-plant sampling records distinguish systems, sample points, raw water and finished water. - Illinois EPA Consumer Confidence Report guidance
Illinois monitoring for raw and finished water at participating public water systems. - EPA local drinking-water information
Federal guidance for identifying the supplier and annual Consumer Confidence Report. - EPA UCMR data finder
Unregulated-contaminant monitoring searchable by system, state, analyte and source-water type. - EWG Illinois utility directory
Independent comparison source; use alongside official utility and regulatory records.
Limit: database records can lag current utility operations. Always compare the record with the newest report and current service account.