Chelmsford Water Hardness & Quality Report (2026)

Chelmsford, Massachusetts, in Middlesex County — a major north Middlesex County suburban community (Chelmsford is a significant Middlesex County town in the greater Lowell–Lawrence suburban corridor — a primarily residential community with a significant tech and biotech professional population, one of the many Route 3 corridor towns that have experienced major growth since the 1970s and 1980s tech boom), home of a major Kronos Incorporated campus (a significant tech employer in the Chelmsford area), adjacent to Lowell in the Merrimack Valley, and a diverse Middlesex County community with a significant South Asian-American and Cambodian-American population — draws its municipal water supply via the Chelmsford Water District. Water hardness in Chelmsford measures 123 mg/L — classified as moderately hard.

Chelmsford's moderate hardness — notably harder than typical Massachusetts soft water — reflects the local supply's geology. The Chelmsford Water District draws from: the Nashoba Terrane calcareous-poor gneiss and schist aquifer (calcareous-poor); and the Chelmsford Granite (calcareous-moderate — the Chelmsford Granite formation, a specific north Middlesex County granite variety known for moderate dissolved mineral content). The Chelmsford Granite quarrying history reflects locally higher mineral content, producing the moderate 123 mg/L.

At 123 mg/L, Chelmsford residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. Chelmsford Water District consistently delivers water meeting all Massachusetts DEP and EPA Safe Drinking Water Act requirements.