Rochester Water Hardness & Quality Report (2026)

Rochester, New York draws its municipal water supply exclusively from Hemlock Lake and Canadice Lake — two of the Finger Lakes system in Livingston and Ontario Counties — managed by the Monroe County Water Authority (MCWA) and distributed throughout Rochester in Monroe County. These protected catchments drain approximately 160 square miles of forested and agricultural Finger Lakes countryside, and are treated at the Shoremont Water Treatment Plant and the Metzger Road facility. No groundwater is blended into the Rochester supply. Water hardness measures 171.5 mg/L — classified as hard — a consistent characteristic of Finger Lakes surface water.

Rochester's hard supply reflects the geology of the Hemlock–Canadice watershed. Both lakes sit in deep valleys carved by the Laurentide Ice Sheet through sequences of Devonian-age Tully Limestone, Hamilton Group shale, and Onondaga Limestone — carbonate-rich sedimentary formations that characterise the Finger Lakes region. As precipitation drains through glacial till deposited over this limestone bedrock, calcium and bicarbonate leach into catchment streams before entering the lake storage. The consistent carbonate signature across the watershed means hardness levels remain relatively stable through seasonal variation.

With hardness at 171.5 mg/L, Rochester residents encounter regular scale accumulation in kettles, on showerheads, and around bathroom fixtures — monthly descaling is a practical maintenance routine. Dishwashers produce noticeably better results with rinse-aid, and glassware without it often shows white mineral film after cycles. Water heaters benefit from annual professional inspection or DIY descaling to maintain heating element efficiency. MCWA has received awards for water quality, and the supply consistently meets all EPA health standards, but hard-water appliance care remains an important household consideration.