Malden Water Hardness & Quality Report (2026)

Malden, Massachusetts, in Middlesex County immediately north of Boston — a densely populated MBTA Orange Line city undergoing significant revitalization with a major Asian-American community — draws its municipal water supply from the Quabbin Reservoir and Wachusett Reservoir via the Massachusetts Water Resources Authority (MWRA) metro north district, distributing Central Massachusetts reservoir water through the MWRA metro north transmission to the inner suburban north Boston corridor including Malden. Water hardness in Malden measures 112.5 mg/L — classified as moderately hard.

Malden's moderate hardness — substantially higher than the soft Quabbin Reservoir source (the Quabbin's source hardness is approximately 10–20 mg/L from the Swift River granite and schist watershed) — reflects the MWRA metro north district's aged distribution infrastructure serving the dense inner suburban north Boston corridor. Malden is one of the most densely built inner suburbs of Boston — the MWRA distribution mains in Malden include cast-iron infrastructure dating from the 1890s–1930s period of Malden's industrial and residential build-out (Malden was a major rubber goods and varnish manufacturing city). The aged distribution infrastructure accumulates substantial mineral content from the soft Quabbin source, producing the elevated 112.5 mg/L at Malden.

At 112.5 mg/L, Malden residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. MWRA consistently delivers water meeting all Massachusetts MassDEP and EPA Safe Drinking Water Act requirements.