Dorchester County, South Carolina: drinking water report. Dorchester County lies inland from Charleston, home to about 170,000 residents in Summerville and…
Dorchester County lies inland from Charleston, home to about 170,000 residents in Summerville and surrounding communities. Dorchester County Water and Sewer draws from the Edisto River and groundwater. The county's rapid growth as a Charleston suburb has increased water demand and infrastructure expansion.
Dorchester County's sources are generally clean. The Edisto River is the longest free-flowing blackwater river in North America, with minimal industrial contamination. UCMR5 data shows low-level PFAS detections in some county systems. The county does not host major military installations, though it borders Joint Base Charleston's airfield.
According to the South Carolina DHEC's 2024 monitoring data, county systems met all federal standards.
Dorchester County's water quality is generally good. Growth-related infrastructure expansion is the main dynamic.
Check your water for data in your area. A carbon filter handles taste concerns. 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 Dorchester County, SC.
The EPA places Dorchester 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.
22% of homes in Dorchester County, SC were built before 1980, and 2% 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 Dorchester County, SC averages 7.9 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
20 public water systems serving Dorchester County, SC have EPA lead testing on record. The reported lead sample skews toward systems that already flagged a problem, so its exceedance rate is not directly comparable with other areas. 2 water systems serving Dorchester County, SC carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Gross Alpha (excl. radon & uranium) | 1 |
| Total Trihalomethanes (TTHM) | 1 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.