Chester Water Hardness & Quality Report (2026)

Chester, Pennsylvania, the Delaware County seat — a major southeast Pennsylvania Delaware River industrial city (Chester is Delaware County's largest city and one of the oldest cities in Pennsylvania — one of the first settlements in William Penn's Pennsylvania colony, originally called Upland by the Swedish settlers before Penn renamed it Chester), home of Subaru Park (the home stadium of the Philadelphia Union MLS soccer team — Subaru Park in Chester is a premier soccer-specific stadium on the Delaware River waterfront, one of the earliest and most celebrated Major League Soccer stadiums), a diverse Delaware County community with a significant African-American majority population (Chester is a majority Black city with one of the highest poverty rates in Pennsylvania), and a historic Delaware River industrial city undergoing significant waterfront redevelopment — draws its municipal water supply from the Delaware River via Aqua Pennsylvania. Water hardness in Chester measures 135 mg/L — classified as moderately hard.

Chester's moderate hardness reflects the Delaware River watershed's calcareous-moderate southeastern Pennsylvania geology. The Delaware River at Chester–Delaware County draws from: the Cambrian–Ordovician Conestoga Limestone (highly calcareous — the primary southeast Pennsylvania Great Valley carbonate); and the Precambrian–Paleozoic Wissahickon Schist (calcareous-poor to moderate — the primary Philadelphia Piedmont metamorphic basement). Aqua Pennsylvania treatment produces the moderate 135 mg/L.

At 135 mg/L, Chester residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. Aqua Pennsylvania consistently delivers water meeting all Pennsylvania DEP and EPA Safe Drinking Water Act requirements.