Sterling Water Hardness & Quality Report (2026)

Loudoun Water is the primary utility serving Sterling, Virginia, in Loudoun County. The drinking water is sourced from the Potomac River and supplemented by Goose Creek as needed. Water is treated at the Alex S. McGrath Water Treatment Plant, which processes raw water through coagulation, sedimentation, filtration, and chloramine disinfection to meet Safe Drinking Water Act standards enforced by the Virginia Department of Health. The service area covers residential and commercial customers across Loudoun County, and annual Consumer Confidence Reports are provided via bill notices with links to detailed quality data.

The Potomac River watershed spans 14,670 square miles across four states and the District of Columbia, with Sterling's supply drawn from the tidal freshwater reach near the fall line. Underlying geology features metamorphic and igneous rocks of the Piedmont province transitioning to unconsolidated sands, clays, and gravels of the Coastal Plain, with limestone and dolostone influences from upstream tributaries like Goose Creek draining Catoctin Mountain formations. This mixed Triassic sedimentary and carbonate geology imparts a moderately mineralised character to the water, elevating natural calcium and magnesium content.

Moderately hard water leads to moderate scale buildup in pipes, water heaters, dishwashers, and washing machines over time, reducing efficiency and lifespan. White deposits may appear on fixtures and soap lather is reduced. Regular maintenance includes descaling heaters annually, cleaning aerators monthly, and using vinegar soaks for showerheads; a water softener is recommended for households noticing these effects. Loudoun Water meets all primary and secondary EPA standards; treatment uses chloramine for disinfection. No PFAS data is detailed in retrieved sources, but the utility complies with Virginia Department of Health monitoring.