Mount Kisco Water Hardness & Quality Report (2026)

The Mount Kisco Water Department supplies about 11,000 residents in Westchester County, New York, drawing exclusively from local groundwater wells. These wells tap into bedrock aquifers within the Croton Highlands sub-basin. All water is treated at the department's facilities, undergoing disinfection and basic filtration before distribution through the municipal pipe network, which meets New York State Department of Health standards. The primary source is groundwater, with no reliance on surface water bodies like reservoirs or rivers.

The water originates from fractured bedrock aquifers formed by Cambro-Ordovician limestones and dolostones, notably the Stockbridge Group, within the Highlands region. These carbonate rocks, prevalent in Westchester County, are naturally rich in minerals like calcium and magnesium. As groundwater percolates through these formations, these minerals dissolve into the water, creating a characteristically hard water supply common to the region's geology.

This very hard water leads to noticeable scale buildup in appliances such as pipes, water heaters, dishwashers, and washing machines, which can reduce their efficiency and lifespan. You'll likely see white deposits on kettles and faucets, and you might find that soap doesn't lather easily, requiring more detergent for cleaning. To combat this, homeowners often need to descale appliances every year or two. Installing a water softener is highly recommended to protect your plumbing and improve washing effectiveness. The water is generally compliant with EPA standards, with pH typically between 7.2 and 7.8, and the utility actively manages manganese and iron levels.