Washington Square Water Hardness & Quality Report (2026)

Washington Square in Philadelphia, Pennsylvania, receives its water from the Philadelphia Water Department (PWD). The supply originates from two major surface water sources: the Schuylkill River and the Delaware River. Water drawn from the Schuylkill is treated at the Queen Lane, Belmont, and Queen Lane Treatment Plants, while water from the Delaware is processed at the Baxter Water Treatment Plant. Together, these facilities manage a vast system that supplies over two million residents across Philadelphia County and surrounding areas, with a combined treatment capacity of more than 600 million gallons daily. The primary watersheds feeding these sources are the Schuylkill River Basin and the Delaware River Basin.

The water's journey begins in the Appalachian Piedmont region, where it flows over ancient metamorphic and igneous bedrock, including Wissahickon Formation schists and gneisses dating back to the Proterozoic Eon. Further upstream, the water picks up dissolved minerals like calcium and magnesium carbonates from limestone and dolostone formations within the Valley and Ridge province, specifically from Chickies Quartzite and Ledger Dolomite layers of Cambrian age. This geological makeup, combined with seasonal flow variations that can concentrate minerals during drier periods, results in a moderately mineralized water profile.

This moderately hard water can lead to noticeable scale buildup in household appliances such as kettles, dishwashers, and water heaters, gradually decreasing their efficiency and potentially increasing energy bills. You might also find that laundry detergents don't perform as effectively, requiring more product for adequate cleaning, and glassware could show spotting after washing. Appliances like coffee makers and washing machines are particularly susceptible to the effects of scale. To combat these issues, homeowners can regularly descale appliances using vinegar and change filters as recommended. For those concerned about the impact on their sensitive equipment or simply preferring softer water, installing a water softener is a common solution. The PWD actively manages the water's pH, keeping it between 7.0 and 8.5 to help control corrosion within the distribution system.