Medford Water Hardness & Quality Report (2026)

Medford Water Department serves approximately 56,787 residents in Medford, Massachusetts (Middlesex County), purchasing treated surface water from the Massachusetts Water Resources Authority (MWRA). MWRA sources water primarily from Quabbin Reservoir, supplemented by Wachusett Reservoir. Water is treated at the John J. Carroll Water Treatment Plant in Marlborough, MA, using ozonation, chloramination, and ammonia addition for disinfection, plus fluoridation for dental health. Distribution reaches Medford and surrounding MWRA communities via extensive pipelines.

The Quabbin Reservoir watershed spans 121 square miles of protected forested land in central Massachusetts, managed to minimize pollution. Underlying geology consists of hard Paleozoic metamorphic rocks — schists and gneisses from Ordovician-Devonian eras — with granitic intrusions and thin glacial till soils. The absence of carbonate rocks like limestone means minimal dissolved calcium and magnesium enter the supply. Wachusett Reservoir draws from similar New England upland geology, yielding comparably soft, pristine surface water.

This soft water profile prevents scale buildup in pipes, appliances, and fixtures, eliminating the need for softening equipment. Soap and detergents lather easily, glassware rinses spot-free, and laundry results are naturally bright. Energy efficiency in water heaters and dishwashers is preserved as limescale cannot form. Water quality meets and exceeds EPA standards per MWRA reports; pH entering systems is approximately 7.0–7.3. Lead testing at high-risk sites with pre-1986 pipes occasionally exceeds the 15 ppb action level — free testing and pipe replacement aid is available. No notable PFAS, radiological, or other violations have been reported; treatment includes ozone disinfection, chloramination, pH adjustment with lime, and corrosion control via orthophosphate.