Jackson Water Hardness & Quality Report (2026)

Jackson, Mississippi draws its municipal water supply from the City of Jackson Department of Public Works, operating two surface water treatment facilities that draw from the Ross Barnett Reservoir — a large impoundment on the Pearl River in Rankin and Madison Counties just east of the city. The O.B. Curtis Water Treatment Plant and the J.H. Fewell Water Treatment Plant process Pearl River water before distribution throughout Jackson in Hinds County. The Pearl River at the reservoir drains the central Mississippi uplands, and despite persistent infrastructure challenges that have affected the Jackson water system in recent years, the source water quality at the reservoir itself remains a regional resource. Water hardness measures 121.5 mg/L — classified as moderately hard.

Jackson's moderate hardness reflects the geology of the Pearl River watershed in central Mississippi. The upper Pearl River drains the North Mississippi Uplands where the terrain crosses Cretaceous Selma Chalk — a regionally extensive chalky limestone formation that contributes calcium bicarbonate to surface drainage across north-central Mississippi. As the river flows south toward Ross Barnett Reservoir, it also traverses terrain underlain by the Eocene Jackson Group — a sequence of calcareous clay, marl, and sandy limestone that forms the geological foundation beneath central Jackson. These marine Tertiary carbonate formations contribute the moderate dissolved calcium characteristic of the Pearl River system.

With hardness at 121.5 mg/L, Jackson residents encounter moderate scale accumulation in household use. Faucet aerators and showerheads develop deposits over several months — monthly cleaning with citric acid descaler is a practical routine. Dishwashers produce cleaner results with rinse-aid, and water heaters benefit from annual inspection. The City's Public Works Department continues to invest significantly in water system infrastructure rehabilitation to address service reliability issues.