Leominster Water Hardness & Quality Report (2026)

Leominster, Massachusetts, in Worcester County — a major north-central Massachusetts city, birthplace of John Chapman (Johnny Appleseed, the famous American folk hero and pioneer orchardist), the 'Plastic City' (Leominster was the world center of the hard plastic comb manufacturing industry in the early 20th century and later a major plastic manufacturing hub — Foster Grant sunglasses were invented in Leominster in 1929), and a diverse Worcester County manufacturing and residential community — draws its municipal water supply from the Notown Reservoir and Monoosnoc Brook watershed via the City of Leominster Water Division. Water hardness in Leominster measures 68.5 mg/L — classified as moderately soft.

Leominster's moderate softness reflects the north-central Massachusetts upland watershed's calcareous-poor crystalline geology. The Notown Reservoir and Monoosnoc Brook watersheds drain: the Leominster–Lancaster Highlands (Devonian–Silurian calcareous-poor Leominster Diorite and Fitchburg plutonic complex — calcareous-poor intrusive igneous terrain); and the Wachusett Mountain area (Precambrian–Ordovician calcareous-poor gneiss and schist of the central Massachusetts crystalline core). The calcareous-poor granite and diorite watershed produces the soft 68.5 mg/L at Leominster.

With hardness at 68.5 mg/L, Leominster residents enjoy moderately soft water. City of Leominster Water Division consistently delivers water meeting all Massachusetts MassDEP and EPA Safe Drinking Water Act requirements.