Source document
Chicago, IL 1997 Consumer Confidence Report
The original annual drinking-water report. Every number on the Chicago, IL water quality page is pulled from this document.
The Chicago, IL figures for 1997 come from EPA's national Safe Drinking Water database (SDWIS / ECHO) — not a single utility-published PDF. Every value on the Chicago, IL water quality page is transcribed from that public dataset, and you can verify it against the same source below.
View the source dataset ↗https://echo.epa.gov/tools/data-downloads/sdwa-download-summary