Lawrence Water Hardness & Quality Report (2026)

Lawrence, Massachusetts — a historic mill city in Essex County at the Merrimack River falls, known for the 1912 Bread and Roses Strike — draws its municipal water supply directly from the Merrimack River via the City of Lawrence Water Division, treating Merrimack River water at the Lawrence Water Treatment Plant serving the densely populated urban Lawrence area. Lawrence is one of the few Massachusetts cities still relying on direct river withdrawal from the Merrimack. Water hardness in Lawrence measures 62 mg/L — classified as moderately soft.

Lawrence's moderately soft supply reflects the Merrimack River watershed's predominantly ancient crystalline geology in New Hampshire and northern Massachusetts. The Merrimack River drains: the White Mountains (Devonian White Mountain Plutonic Series — Conway Granite, Franconia Granite — very calcium-poor crystalline rock); the New Hampshire Penobscot-Merrimack terrane (Silurian–Devonian metasedimentary schist and quartzite); the Precambrian Milford Granite and related New Hampshire Proterozoic basement; and the Ossipee Mountains (Jurassic ring-dike intrusion — silicic). These ancient granitic and metamorphic terranes contribute minimal dissolved calcium, producing the moderately soft Merrimack River supply that Lawrence treats and distributes. The 62 mg/L hardness is typical for a Merrimack River source downstream of the White Mountains.

With hardness at 62 mg/L, Lawrence residents experience minimal to moderate scale challenges. Faucet aerators and showerheads develop deposits slowly — bi-monthly cleaning with citric acid solution is sufficient. City of Lawrence Water Division consistently delivers water meeting all Massachusetts DEP and EPA Safe Drinking Water Act requirements.