Columbia Heights Water Hardness & Quality Report (2026)

Columbia Heights, Washington, DC — a vibrant and historically significant DC neighborhood, one of the most diverse urban neighborhoods in the United States (Columbia Heights is home to large Central American — primarily Salvadoran, Guatemalan, and Honduran — communities, and a historically significant African-American community, along with a rapidly growing influx of young professionals), a major DC nightlife and restaurant corridor (the 14th Street corridor — one of DC's most dynamic mixed-use urban corridors), and a neighborhood that experienced devastating 1968 DC riots (following Martin Luther King Jr.'s assassination) and subsequent decades of disinvestment before revitalizing in the 2000s–2010s — draws its municipal water supply from the Potomac River via the DC Water (WASA). Water hardness in Columbia Heights measures 138 mg/L — classified as moderately hard.

Columbia Heights's moderate hardness reflects the Potomac River supply and DC Water distribution characteristics in the northwest DC zone. The Potomac River at Great Falls carries: Appalachian Highlands calcareous drainage (the Shenandoah Valley calcareous limestone and dolomite); the Virginia Blue Ridge calcareous schist and calcareous amphibolite. DC Water treats the Potomac supply at the Dalecarlia and McMillan facilities, and the Columbia Heights northwest DC distribution zone (late 19th–early 20th century mains from the Columbia Heights streetcar suburb era) produces the moderate 138 mg/L.

At 138 mg/L, Columbia Heights residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. DC Water consistently delivers water meeting all DC DOH and EPA Safe Drinking Water Act requirements.