Kennedy Street Water Hardness & Quality Report (2026)

Kennedy Street, in the District of Columbia — a DC neighborhood adjacent to Brightwood and Petworth in upper northwest DC near the Maryland border — receives its water from DC Water, drawing from the Potomac River at the Washington Aqueduct (McMillan and Dalecarlia Reservoirs) through the DC distribution system.

The moderately hard 113 mg/L hardness and TDS of 253.4 mg/L are consistent with the DC Washington Aqueduct Potomac supply (DC average: ~115-120 mg/L) — the classic moderately hard Potomac character driven by the Virginia-Maryland Blue Ridge calcareous input. The Potomac River at the Washington Aqueduct drains the Virginia Blue Ridge — Precambrian Catoctin Greenstone (insoluble — significant dilutant), Triassic Culpeper Basin (calcareous redbed — moderate hardness contributor), and Cambrian Conococheague Formation (calcareous — primary hardness contributor). The Triassic and Cambrian calcareous input produces the moderately hard DC supply.

At 113 mg/L, Kennedy Street'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 reverse osmosis drinking water filter — Marine Corps Base Quantico (Prince William County — AFFF), Fort Belvoir (Fairfax County — AFFF), and the Potomac River upper watershed military-industrial PFAS complex contribute to Kennedy Street's elevated readings.