Source document
City of Cupertino, CA 2025 Consumer Confidence Report
The original annual drinking-water report. Every number on the City of Cupertino, CA water quality page is pulled from this document.
The City of Cupertino, CA figures for 2025 come from California's SDWIS Electronic Data Transfer (EDT) library — not a single utility-published PDF. Every value on the City of Cupertino, CA water quality page is transcribed from that public dataset, and you can verify it against the same source below.
View the source dataset ↗https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/EDTlibrary.html