H Street NE Water Hardness & Quality Report (2026)

DC Water (District of Columbia Water and Sewer Authority) provides water service to H Street NE in Washington, D.C., sourcing primarily from the Potomac River via the Washington Aqueduct, operated by the U.S. Army Corps of Engineers. Key intake points include the Potomac River at Great Falls and Seneca, with backup from the Patuxent River. Treatment occurs at the Washington Aqueduct plants (Dalecarlia and Potomac), serving over 1.8 million people across D.C., Arlington, and Fairfax County in Virginia. Distribution covers the entire District, including Northeast quadrants like H Street NE.

The Potomac River watershed spans 14,670 square miles across West Virginia, Virginia, Maryland, and D.C., with headwaters in the Appalachian Plateau. Underlying geology features sedimentary layers of the Potomac Group (Cretaceous sands and clays) and Coastal Plain deposits (Tertiary and Quaternary unconsolidated sediments), interspersed with limestone outcrops from Ordovician through Devonian periods upstream. This karst-influenced terrain leaches calcium and magnesium into runoff and shallow aquifers, yielding a moderately mineralised supply prone to seasonal peaks from limestone dissolution during low-flow summer periods.

Moderately hard water in D.C. causes scale buildup in dishwashers, washing machines, and water heaters, leading to spotting on glassware, film on fixtures, and reduced appliance efficiency. Showers and faucets may show white residue, especially in warmer months. Periodic vinegar descaling, rinse aids in dishwashers, and sediment filters help manage hardness; a water softener is recommended for households with frequent spotting. DC Water maintains EPA compliance; recent assessments note pH 7.2–7.8, full lead/copper rule adherence via corrosion control, no PFAS exceedances in the 2023 CCR, and treatment involving coagulation, sedimentation, filtration, chloramination, and fluoride addition.