Charleston County, South Carolina: drinking water report. Charleston County serves about 410,000 residents in the South Carolina Lowcountry.
Charleston County serves about 410,000 residents in the South Carolina Lowcountry. Charleston Water System draws from the Bushy Park Reservoir and the Edisto River, supplemented by groundwater. The county's coastal setting creates challenges from saltwater intrusion, sea level rise, and hurricane vulnerability.
Charleston's drinking water sources are surface water, which avoids many groundwater contamination issues but introduces seasonal variability from stormwater runoff and tidal influence. UCMR5 data shows low-level PFAS detections in county systems. Joint Base Charleston (formerly Charleston Air Force Base) is a confirmed PFAS source.
According to the South Carolina DHEC's 2024 monitoring data, PFAS levels in the Charleston Water System were below proposed federal MCLs. Sea level rise and increased flooding from king tides and hurricanes threaten coastal infrastructure and can cause temporary water quality disruptions.
Charleston County's coastal vulnerability makes water quality a moving target. Hurricane season brings the highest risk of disruption.
Check your water for data in your area. Reverse osmosis handles PFAS and coastal water quality variability. Our water filter guide covers options. Pull your detailed report, and visit our South Carolina page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Charleston County, SC.
The EPA places Charleston County, SC in Zone 3 - the EPA's lowest-risk category, with a predicted average indoor radon level below 2 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
37% of homes in Charleston County, SC were built before 1980, and 9% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Charleston County, SC averages 7.8 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide