Chambersburg Water Hardness & Quality Report (2026)

Chambersburg, Pennsylvania, in Franklin County — the Franklin County seat in south-central Pennsylvania's Cumberland Valley, an important Civil War-era city (the only Northern city burned by Confederate troops in 1864 — McCausland's Raid), a Route 30 and Interstate 81 corridor commercial and agricultural hub — receives its municipal water from the Borough of Chambersburg Municipal Authority, which draws from the Conococheague Creek and spring sources in the limestone valley of the Cumberland Valley's Great Valley province.

The moderately hard 131 mg/L hardness and TDS of 252.5 mg/L reflect Chambersburg's Great Valley limestone watershed geology. Conococheague Creek drains the Cumberland Valley (the Pennsylvania segment of the Great Valley physiographic province) — underlain by the Cambrian-Ordovician carbonate sequence: the Elbrook Formation (dolomite), the Conococheague Formation (limestone and dolostone), and the Beekmantown Group (massive carbonate platform). These Cambrian-Ordovician limestones and dolomites form the productive carbonate aquifer of the Cumberland Valley, dissolving readily to produce moderately hard spring and stream water throughout the Great Valley south of South Mountain.

At 131 mg/L, Chambersburg's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 6.8 ppt warrants a certified drinking water filter — the Letterkenny Army Depot (a major US Army maintenance and weapons storage facility directly adjacent to Chambersburg — a significant AFFF user and industrial solvent site), and the Franklin County agricultural-industrial corridor contribute to Chambersburg's PFAS reading.