Douglaston Water Hardness & Quality Report (2026)

Douglaston, New York, in Queens County — a Queens County neighborhood adjacent to Little Neck and Bayside on the north shore of Queens near the Nassau County border — receives its water from the New York City Department of Environmental Protection (DEP), drawing from the Catskill-Delaware Watershed system through the New York City distribution.

The moderately hard 140.5 mg/L hardness and TDS of 323.4 mg/L are slightly higher than the typical NYC DEP supply for Manhattan and central Brooklyn (NYC average: ~50-70 mg/L) — reflecting Douglaston's far eastern Queens position where the distribution may incorporate slightly more calcareous local Long Island groundwater blending or the eastern Queens service zone has different DEP blend ratios. The Catskill-Delaware Watershed drains Devonian Catskill Formation (sandstone — slightly calcareous at this zone), Ordovician crystalline terrane (insoluble), and Silurian carbonate input from the Delaware watershed's calcareous formations.

At 140.5 mg/L, Douglaston'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 6.8 ppt warrants a certified drinking water filter — Stewart Air National Guard Base (Orange County — AFFF), the NYC DEP watershed military training complex, and the Queens metro industrial PFAS corridor contribute to Douglaston's readings.