Pleasant Plains Water Hardness & Quality Report (2026)

Pleasant Plains, District of Columbia — a historic Shaw-Columbia Heights corridor neighborhood in Northwest DC, a historically African American community with deep civil rights heritage adjacent to the Howard University campus and the U Street Corridor — receives its municipal water from DC Water (DC Water and Sewer Authority), which draws from the Potomac River at the Dalecarlia and McMillan water treatment plants on the upper DC reach of the Potomac. All DC neighborhoods receive the same DC Water Potomac River supply.

The moderately hard 120.5 mg/L hardness and TDS of 284.9 mg/L reflect the Potomac River watershed's mixed geological character at the Washington DC reach. The Potomac River drains a large and geologically complex watershed spanning the Blue Ridge Mountains (Precambrian crystalline rocks — granodiorite and metabasalt, soft), the Valley and Ridge (Ordovician Martinsburg Shale, Silurian limestone, Devonian Helderberg Limestone — carbonate contributor), the Great Valley (Hagerstown Valley limestone), and the Piedmont (the Triassic Culpeper Basin redbeds — calcareous sandstone and shale). The blended watershed produces moderate hardness at the DC intake — harder than pure Blue Ridge supplies but softer than the more calcareous central Appalachian rivers.

At 120.5 mg/L, Pleasant Plains' water is moderately hard — consistent with DC's Potomac River supply. Scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 8.1 ppt warrants a certified drinking water filter — the Potomac River watershed's extensive military installations (Fort Meade, Aberdeen Proving Ground, Quantico Marine Corps Base), the Dulles Corridor aerospace and defense industry, and the Washington DC metro industrial complex contribute to the Potomac's documented PFAS loading.