Source document
Niles, IL 1998 Consumer Confidence Report
The original annual drinking-water report. Every number on the Niles, IL water quality page is pulled from this document.
The Niles, IL figures for 1998 come from EPA's national Safe Drinking Water database (SDWIS / ECHO) — not a single utility-published PDF. Every value on the Niles, 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