Centreville Water Hardness & Quality Report (2026)

Fairfax Water serves Centreville in Fairfax County, Virginia, supplying drinking water to over 1.8 million residents across Northern Virginia. Primary sources are the Potomac River, treated at the James J. Corbalis Jr. Treatment Plant with a capacity of 225 million gallons per day, and the Occoquan Reservoir, processed at the Frederick P. Griffith Treatment Plant handling up to 120 million gallons daily. Centreville receives this blended surface water supply, which undergoes conventional treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA standards.

The Potomac River watershed spans 14,670 square miles across West Virginia, Maryland, Virginia, and the District of Columbia, draining terrains from Appalachian highlands to coastal plain. The Occoquan River watershed covers 622 square miles of forested Piedmont uplands. Geology features fractured metamorphic and igneous rocks in the Piedmont leaching minerals into runoff and baseflow, with natural dissolved solids from limestone outcrops and Triassic Culpeper Basin sediments contributing to a moderately mineralised supply without reliance on groundwater aquifers.

As moderately hard water, the supply promotes scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan while increasing energy costs by up to 20–30%. Soap lathering is less effective, leaving residues on skin, hair, and laundry. Regular descaling of fixtures, installing drain screens, and flushing hot water heaters annually are recommended; a water softener is advised for households noticing spotting on glassware or dry skin. Fairfax Water's 2025 Consumer Confidence Report confirms full regulatory compliance; pH is typically neutral to slightly alkaline from natural buffering.