Fenway/Kenmore Water Hardness & Quality Report (2026)

The Massachusetts Water Resources Authority (MWRA) supplies water to Fenway/Kenmore in Boston, serving over 3 million people across 51 communities in Greater Boston via the MetroWest Water Supply System. The primary source is the Quabbin Reservoir (120 billion gallons capacity), supplemented by Wachusett Reservoir, both in central Massachusetts. Water travels over 100 miles through the MetroWest Tunnel to the John J. Carroll Water Treatment Plant in Marlborough, then through distribution tunnels to Boston, where the Boston Water and Sewer Commission (BWSC) handles local distribution in Fenway/Kenmore.

The Quabbin and Wachusett Watersheds — protected forested areas spanning 412 square miles with strict land use controls — overlie the hard, resistant igneous and metamorphic rocks of the Appalachian province, including granite, quartzite, and schist from Ordovician–Devonian periods, formed in part from the Brimfield Schist and Marlboro Formation. With no significant limestone or dolomite and no karst or evaporite formations present, the watershed yields very soft water, as bedrock contributes negligible calcium or magnesium to surface waters; surface runoff from forested uplands and thin glacial till further limits mineral pickup.

As soft water, this supply minimizes scale buildup in pipes, water heaters, and appliances, reducing energy costs and maintenance needs. No significant spotting on glassware or fixtures; skin and hair feel smoother without mineral residue; dishwashers and laundry machines perform efficiently without softeners, and detergents lather and rinse cleanly. A water softener is not recommended and could overly strip beneficial minerals; occasional vinegar rinses suffice for any minor deposits. MWRA maintains pH at 9.0–9.5 post-treatment for corrosion control via orthophosphate dosing; no recent PFAS detections above limits; perchlorate absent since 2011; treatment at Carroll Plant includes ozonation, chloramination, and UV disinfection; water consistently earns top taste awards, with BWSC monitoring for occasional turbidity from pipe sediments.