Wolf Trap Water Hardness & Quality Report (2026)

Fairfax Water supplies Wolf Trap, Virginia, drawing from a mix of sources including the Potomac River and the Occoquan Reservoir. The utility serves over 1.7 million people across Fairfax County and northern Virginia. Water intake for the Potomac River occurs at Great Falls, while the Occoquan Reservoir is also a primary source. Treatment takes place at significant facilities like the Frederick P. Griffith Treatment Plant and the Corbalis Treatment Plant, which processes water from the Potomac supplies. These surface waters are blended and distributed through an extensive pipeline network.

The Potomac River watershed begins in the Appalachian highlands and flows through regions rich in Devonian and Ordovician limestones, such as the Keyser and Tonoloway formations. These carbonate rocks contribute calcium and magnesium, imparting hardness. The Occoquan Reservoir watershed, however, is primarily underlain by older Piedmont rocks and younger Coastal Plain sands and gravels. This geological transition, from karst-influenced sedimentary bedrock to looser deposits, results in a moderately mineralized water supply typical of the area.

Homeowners in Wolf Trap may notice scale buildup on appliances like water heaters and dishwashers, which can reduce their efficiency and lifespan. Faucets and fixtures might also develop white deposits. Regular descaling with vinegar can help manage these issues, as can using detergents formulated for hard water. For persistent scaling problems and to improve how soap lathers, installing a water softener is often recommended, though it's not a health necessity. Fairfax Water also works to control corrosion by maintaining a pH between 7.5 and 8.5, and has reported no exceedances for lead or copper.