North Charleston Water Hardness & Quality Report (2026)

North Charleston, South Carolina, the third-largest city in South Carolina and a major Charleston metropolitan hub, draws its municipal water supply from the Commissioners of Public Works (CPW) of Charleston and the North Charleston Water System, sourcing from both the Edisto River surface water system (via the Hanahan Water Treatment Plant — the same regional infrastructure as Charleston) and local coastal plain aquifer groundwater from the Middendorf aquifer and Tertiary limestone aquifer in Charleston County. Water hardness in North Charleston measures 142 mg/L — classified as moderately hard, notably harder than Charleston proper (60 mg/L), reflecting the higher reliance on coastal plain groundwater in the North Charleston distribution zone.

North Charleston's harder supply compared to downtown Charleston reflects the greater groundwater fraction in the North Charleston distribution network. While Charleston's CPW supply is primarily the soft Edisto River surface water, the North Charleston distribution area draws a higher proportion of Charleston County coastal plain groundwater — from the Cretaceous Middendorf Formation (moderately calcareous sandstone and clay) and the Tertiary Santee Limestone and Castle Hayne Limestone — shallow coastal plain aquifer units that dissolve significant calcium carbonate into groundwater circulating through the calcareous limestone formations near the Charleston coast.

At 142 mg/L, North Charleston residents encounter moderate scale accumulation in household use. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. Dishwashers produce cleaner glassware with rinse-aid, and water heaters benefit from annual inspection for element scale. CPW of Charleston and North Charleston Water System consistently deliver water meeting all South Carolina DHEC and EPA Safe Drinking Water Act requirements.