Billings Water Hardness & Quality Report (2026)

The City of Billings Public Works operates the municipal water system serving approximately 117,000 residents in Yellowstone County, Montana. Water is sourced exclusively from the Yellowstone River at intake points north of the city, treated at the Water Treatment Plant near the river. The system serves the urban core including areas near the Rimrocks and downtown Montana Avenue, with distribution monitored under the Safe Drinking Water Act. No groundwater aquifers are utilized; the supply relies entirely on the Yellowstone River as its surface water source.

The Yellowstone River watershed spans over 70,000 square miles, originating in Yellowstone National Park and flowing through Wyoming and Montana. The river erodes Cretaceous and Tertiary limestone and sandstone formations prevalent in the Bighorn Basin upstream — including the Madison Limestone and Eagle Sandstone equivalents — dissolving calcium and magnesium ions into the water. The surface water's mineral profile reflects prolonged contact with these carbonate rock layers; susceptibility to contamination from agricultural and industrial sources is rated low per city assessments.

Hard water at 157 mg/L leads to scale buildup in pipes, water heaters, dishwashers, and washing machines, often requiring more frequent descaling or part replacements. Laundry may appear dingy, skin feel dry after bathing, and spots linger on glassware without rinse aids. Regular vinegar flushes and sediment filter checks are advised; a water softener is widely recommended for households. Recent analyses note 4–8 contaminants — including arsenic, chromium-6, and disinfection byproducts — exceeding health guidelines though meeting EPA MCLs. Treatment includes filtration and disinfection; lead/copper rules are met with no recent EPA violations noted.