Sacramento County Water Report

Sacramento County earns a B grade for drinking water quality, scoring 69.0 out of 100. Over the past five years, EPA SDWIS records 22 health-based violations — a pattern that public water utilities are required to disclose and correct.

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 40.8% of assessed waterways are impaired (29 of 71 water bodies) across Sacramento County's watersheds. The leading impairment causes are toxicity and mercury. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

USGS NWIS gauge data (as of 2026-05-14T12:00:00.000-07:00) puts AMERICAN R A FAIR OAKS CA at 3.4k cfs — near its historical average at 95% of mean flow. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Sacramento County has extensive coverage with 98 active monitoring sites with 59,617 recent measurements on record. Predominant monitoring categories include organics, pesticide and physical. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.