Rotterdam Water Hardness & Quality Report (2026)

Rotterdam, New York, in Schenectady County — the Town of Rotterdam, a Schenectady County suburb directly west of Schenectady on the southern Mohawk Valley corridor, a residential community in the Capital District metropolitan area — receives its municipal water from the Schenectady County Water Purification District or the Rotterdam Junction Water District, which draws from the Mohawk River at the Schenectady water plant (the Galway Reservoir or Round Lake supplementary supply) serving the Schenectady-Rotterdam corridor.

The moderately soft 75.5 mg/L hardness and TDS of 123 mg/L reflect the Mohawk Valley supply's consistent Ordovician shale and Silurian geological character — essentially identical to the Latham-Albany supply (72 mg/L, 114 mg/L TDS) on the same Mohawk River-Capital District supply system. The Mohawk River at Schenectady drains the same Ordovician shale and argillite (Utica Shale, Lorraine Group), Silurian calcareous formations, and limited Devonian limestone of the Mohawk Valley, producing consistently moderately soft water throughout the Mohawk-Hudson Capital District supply zone.

At 75.5 mg/L, Rotterdam's water is moderately soft — comfortable for household use. Scale forms slowly over many months, soap lathers well, and appliances operate efficiently. Semi-annual descaling is adequate. The PFAS level of 3.7 ppt is moderate for the Capital District — Schenectady's General Electric manufacturing legacy (GE's historic Schenectady Works — electrical transformers, semiconductor, and chemical R&D), the Knolls Atomic Power Laboratory (nuclear submarine reactor design in Niskayuna), and the broader Capital District's industrial heritage contribute to the Mohawk-Schenectady PFAS background.