Orange County Water Report

Orange County earns a B grade for drinking water quality, scoring 68.8 out of 100. Over the past five years, EPA SDWIS records 24 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 35.3% of assessed waterways are impaired (526 of 1,492 water bodies) across Orange County's watersheds. The leading impairment causes are mercury in fish tissue and phosphorus, total. 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 2026-05-14T14:30:00.000-04:00) puts ST. JOHNS RIVER at 339.0 cfs — well below its long-term average at 26% of mean — low-flow conditions worth noting for water-dependent ecosystems. 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. Orange County has extensive coverage with 933 active monitoring sites with 284,744 recent measurements on record. Predominant monitoring categories include physical and inorganics, minor, metals. 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.