NoMa Water Hardness & Quality Report (2026)

NoMa (North of Massachusetts Avenue), Washington DC — a rapidly gentrifying northeast DC neighborhood adjacent to Union Station and the H Street corridor, one of the fastest-growing urban development zones in the capital — receives its municipal water from DC Water (DC Water and Sewer Authority), which draws from the Potomac River at the Dalecarlia Water Treatment Plant (Georgetown, DC) and the McMillan Distribution Reservoir, serving all of Washington DC.

The moderately hard 113.5 mg/L hardness and TDS of 254.6 mg/L are consistent with the standard DC Water Potomac River supply chemistry — essentially identical throughout the District. The Potomac River at the DC intake drains approximately 14,700 square miles of watershed in West Virginia, Maryland, Virginia, and Pennsylvania — including the crystalline Blue Ridge (very soft), the calcareous Valley and Ridge (Shenandoah Valley limestone and dolomite — hard), and the mixed Piedmont (Triassic Culpeper Basin calcareous redbeds, Precambrian gneiss). The weighted average of this diverse watershed produces the moderately hard, moderate-TDS supply characteristic of the DC Potomac supply system.

At 113.5 mg/L, NoMa's water is moderately hard — 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 7.5 ppt warrants a certified drinking water filter — the Potomac River watershed's dense military complex (Fort Detrick in Frederick MD, Quantico Marine Base, Fort Belvoir), the Dulles Corridor aviation complex, and the broader mid-Atlantic military industrial PFAS legacy contribute to the DC Water supply's PFAS reading.