Minot Water Hardness & Quality Report (2026)

The City of Minot Water Treatment Plant, operated by the City of Minot Public Works Department, supplies drinking water to the city and surrounding communities via the Northwest Area Water Supply (NAWS) system in Ward County, North Dakota. Water is drawn from 16 wells tapping two aquifers: the Sundre Aquifer (contributing 66% of supply in 2024) and the Minot Aquifer (34%). The plant treats groundwater to meet EPA standards for residential, commercial, and firefighting needs.

Minot's groundwater originates entirely from these two aquifers without a surface watershed, shaped by the glacial geology of North Dakota's till plains. The Sundre Aquifer consists of unconsolidated Quaternary glacial sands and gravels, while the Minot Aquifer taps deeper Cretaceous-Tertiary sedimentary layers including limestone formations. Natural dissolution of calcium and magnesium from carbonate-rich strata during long subsurface residence produces a hard to very hard supply, requiring treatment adjustments before delivery.

At 150 mg/L hardness, scale buildup is a primary concern, most severely affecting water heaters, dishwashers, washing machines, and plumbing fixtures by reducing efficiency and lifespan. Spotting on dishes, soap scum, and reduced water pressure from limescale deposits are common household effects. Annual descaling of heaters and scale inhibitors help mitigate issues, but a water softener is strongly recommended for most households. The 2024 Water Quality Report confirms full EPA compliance, with treated water at pH 9.4, hardness 150 mg/L (9 gpg), total dissolved solids 1,490 mg/L, sodium 218 mg/L, and calcium 68 mg/L. Lead levels measured 0 ppb (action level 15 ppb, 90th percentile 13.5 ppb). Treatment includes softening from raw well hardness down to the 100–150 ppm delivery range; no PFAS data is noted in available reports.