Horry County Water Report

Horry County earns a B grade for drinking water quality, scoring 68.4 out of 100. Over the past five years, EPA SDWIS records 7 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 large majority — 66.7% — of assessed waterways are impaired (4 of 6 water bodies) across Horry County's watersheds. The leading impairment causes are escherichia coli (e. coli) and ph. 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 2026-05-14T14:15:00.000-04:00) puts PEE DEE RIVER at 7.3k cfs — running somewhat below its historical average at 76% of mean. 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. Horry County has extensive coverage with 107 active monitoring sites with 42,696 recent measurements on record. Predominant monitoring categories include physical and microbiological. 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.