Myrtle Beach sits at the heart of Horry County — consistently ranked among the fastest-growing counties in the United States, adding over 25,000 residents annually as retirees, remote workers, and vacation-home buyers flood into the Grand Strand region. The rapid pace of development has pushed residential construction into inland Horry County areas that lack municipal sewer service, driving significant demand for new septic installations in a coastal landscape defined by sandy soils, tidal influence, and some of the most ecologically sensitive shellfish harvesting waters on the East Coast. SC DHEC's oversight of septic permitting near shellfish areas is particularly rigorous, and the combination of sandy coastal soils — which drain rapidly but treat poorly — with proximity to tidal creeks means that system siting requires careful attention to nitrogen and pathogen loading in the Myrtle Beach area.
Soil Conditions
Wando and Lakeland soil series are the primary upland soils in the Myrtle Beach area — excessively drained, deep Entisols with fine to medium sand throughout the profile. These soils offer excellent percolation (less than 3 minutes per inch in many locations) but minimal treatment capacity for nutrients and pathogens. Closer to tidal creeks, the Waccamaw and Paxville soils — poorly drained, organic-matter-rich Ultisols and Histosols — have water tables within inches of the surface and cannot support conventional drain fields.
The Wando series (thermic, coated Typic Quartzipsamments) dominates the upland barrier ridges and inland terraces of Horry County. Like Florida's Lakeland soils, Wando is a deep sand with negligible clay or organic matter — offering exceptional drainage but almost no treatment. DHEC's percolation testing requirement often produces rates under 5 minutes per inch for Wando soils, which falls within the acceptable range for conventional systems but raises significant concerns about nutrient and pathogen treatment before effluent reaches the shallow coastal water table. Near tidal creeks, Paxville soils (loamy, siliceous, semiactive, thermic Arenic Paleaquults) have dense clay subsoils that restrict drainage and create seasonally saturated conditions within 12–18 inches of the surface — triggering DHEC requirements for alternative system designs.
Water Table: Upland Wando soils have water tables at 5–10 feet on barrier island ridges and inland terraces. However, proximity to the coast means tidal fluctuations influence groundwater elevation within 0.5–1 mile of tidal waters, and storm surge events can temporarily elevate water tables across wide areas. Low-lying pocosins and Carolina bay wetlands throughout Horry County maintain near-surface water tables year-round.
Local Regulations
SC DHEC's Bureau of Environmental Health Services is the primary regulatory authority for septic systems in Horry County, with local enforcement support from the Horry County Environmental Health Division. DHEC classifies systems into conventional, alternative, and experimental categories under SC Regulation 61-56. All new installations require a site evaluation with soil analysis and percolation testing. Properties within designated Shellfish Condemnation Areas — which cover significant portions of tidal Horry County — face additional DHEC review and may require enhanced treatment systems to protect water quality in designated shellfish growing waters. The Grand Strand's popularity means DHEC's Myrtle Beach regional staff handles some of the highest new permit volumes in the state.
Permits are issued by DHEC's Low Country regional office and the Horry County Environmental Health Division. Horry County is the fastest-growing county in South Carolina, adding tens of thousands of residents annually in planned residential communities, golf course communities, and resort developments. Many new subdivisions in Horry County's inland areas are beyond the reach of Myrtle Beach Area Water and Sewer Authority (MBAWSA) service and require private septic. DHEC reviews systems near shellfish harvesting waters with additional scrutiny. Permit fees range from $200–$450; engineered alternative system designs add $1,000–$3,000.