Mount Pleasant Water Hardness & Quality Report (2026)

Mount Pleasant, Washington, DC — a diverse and historic neighborhood in northwest Washington, DC (Mount Pleasant is one of the most diverse neighborhoods in Washington DC — a significant Latino-American, Central American, and Salvadoran-American community in northwest DC, with a growing young professional population), adjacent to Columbia Heights and Rock Creek Park (the major urban park in northwest DC), home of the Mount Pleasant Library branch (one of DC's most used neighborhood library branches), a neighborhood with a rich social and political activist history (Mount Pleasant was the site of a major 1991 neighborhood protest over police conduct — the Mount Pleasant riot — a landmark event in DC's Latino-American community history), and part of northwest DC's diverse urban neighborhood fabric — draws its municipal water supply via the DC Water Authority. Water hardness in Mount Pleasant measures 110.5 mg/L — classified as moderately hard.

Mount Pleasant's moderate hardness reflects the DC Water supply and northwest DC distribution characteristics. The DC Water Blue Plains system treats the Potomac River (drawing from Virginia Blue Ridge and Piedmont runoff — calcareous-moderate crystalline). The Mount Pleasant northwest DC distribution infrastructure (primarily early 20th century residential neighborhood mains from the 1910s–1930s Columbia Heights–Mount Pleasant buildout) accumulates moderate hardness, producing the moderate 110.5 mg/L.

At 110.5 mg/L, Mount Pleasant residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. DC Water consistently delivers water meeting all DC DOEE and EPA Safe Drinking Water Act requirements.