Overview
Great Falls WWTP serves approximately 58,439 residents in Great Falls, Montana. The facility discharges treated wastewater into the Missouri River, a major tributary of the Mississippi River system.
Great Falls WWTP is a municipal wastewater treatment facility located in Great Falls, Cascade County, Montana, along the Missouri River. The plant serves an estimated population of 58,439, placing it in the medium-agglomeration category under U.S. regulatory frameworks. As a U.S. facility, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Montana Department of Environmental Quality. For agglomerations of this scale, secondary treatment is typically required, with additional nutrient removal standards applicable to sensitive watersheds. The plant's treated effluent discharges into the Missouri River, which flows eastward to join the Mississippi River and ultimately the Gulf of Mexico. The Missouri River supports diverse aquatic life and is a critical water resource for the region, including irrigation, recreation, and downstream communities.
Environmental context
The Missouri River at Great Falls is part of the Upper Missouri River Basin, a region characterized by semi-arid climate and agricultural land use. Downstream, the river flows through the Missouri Breaks and into Lake Sakakawea, a large reservoir on the Missouri River in North Dakota. The watershed supports native fish species such as pallid sturgeon and paddlefish, and the river's flow regime is influenced by upstream dams and irrigation diversions. Treated wastewater discharge must meet state water quality standards to protect aquatic life and downstream uses.
Frequently asked questions
Great Falls WWTP is located along the Rivers Edge Trail in Great Falls, Cascade County, Montana, United States.
The plant serves approximately 58,439 residents, classifying it as a medium-sized municipal wastewater treatment facility.
The treated effluent is discharged into the Missouri River, which flows through Montana and eventually joins the Mississippi River.
Under the Clean Water Act, the plant must obtain an NPDES permit from the Montana Department of Environmental Quality, setting limits on pollutants to protect water quality in the Missouri River.
Facilities of this scale in the U.S. typically provide secondary treatment, which includes biological processes to remove organic matter and suspended solids, and may include nutrient removal if the receiving water is sensitive.
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