Van Ness Water Hardness & Quality Report (2026)

DC Water supplies the Van Ness neighborhood in northwest Washington DC, drawing its primary water from the Potomac River. Raw water enters the system through intakes located on the Potomac River itself, both at the Dalecarlia intake just above Great Falls and another Potomac River intake. Treatment is a multi-facility effort, handled at the Dalecarlia Water Treatment Plant and the adjacent Washington Aqueduct facilities, which are operated by the U.S. Army Corps of Engineers. This extensive system serves the entirety of the District of Columbia, with Van Ness being part of Ward 3.

The Potomac River watershed itself is vast, covering 14,670 square miles and extending into West Virginia, Virginia, Maryland, and DC, with its headwaters originating in the Appalachian Plateau. Upstream geology is characterized by folded Paleozoic sandstones, shales, and limestones, which naturally dissolve and release minerals into the water. Closer to DC, the Fall Line exposes more resistant metamorphic rocks. This geological mix results in water that is moderately mineralized, with bicarbonate ions providing a natural buffering effect. While some shallow groundwater exists in Potomac Group formations, the main supply relies heavily on the river.

Homeowners in Van Ness may notice moderate scale buildup on appliances like dishwashers, washing machines, and water heaters, which can reduce their efficiency over time. You might also see limescale in kettles and soap scum in bathrooms, though these are generally manageable with regular cleaning. Simple steps like using vinegar for descaling and maintaining low-flow fixtures can help mitigate these effects. For those concerned about extending appliance life and improving cleaning power, a water softener is a worthwhile consideration, though not strictly necessary for everyone. Recent assessments show DC Water's supply meets EPA standards, with no issues reported regarding pH or temperature, and lead/copper compliance is maintained through ongoing corrosion control efforts.