Housing Authority City of Caldwell Wastewater Treatment Plant, Canyon County, Idaho

The Housing Authority City of Caldwell wastewater treatment plant serves a small community in Canyon County, Idaho, United States. With a population served of 1,600, it is classified as a small-scale facility. The plant is located in an inland area, far from coastal influences, and operates under the regulatory framework of the US Clean Water Act. The plant provides secondary treatment, which is the standard level required by the US Environmental Protection Agency (EPA) for municipal wastewater. Its designed capacity is 329.33 megaliters, and it currently treats 132.49 megaliters annually, indicating available capacity for future growth. As a publicly owned treatment works (POTW), it is subject to National Pollutant Discharge Elimination System (NPDES) permitting, which sets effluent limits to protect water quality. The treated effluent is discharged into local waterways that drain into the Snake River basin, a major tributary of the Columbia River. The Snake River supports diverse aquatic life and is an important resource for irrigation, recreation, and hydropower in the Pacific Northwest. The plant's operations help maintain water quality in this ecologically significant watershed.

The plant discharges into local streams that flow into the Snake River, which ultimately reaches the Columbia River and the Pacific Ocean. The Snake River basin supports a variety of fish species, including salmon and steelhead, and provides critical habitat for migratory birds. The plant's secondary treatment helps reduce nutrient and pathogen loads, protecting downstream water quality in this agriculturally and ecologically important region.