COSTILLA CO WSD Wastewater Treatment Plant, Costilla County, Colorado

COSTILLA CO WSD is a municipal wastewater treatment plant located in Costilla County, Colorado, serving a small population of 690 residents. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring compliance with federal and state water quality standards. The plant has a designed capacity of 492.10 megaliters and an annual discharge volume of 302.83 megaliters, indicating it operates below capacity. As a facility in the U.S., it is subject to the Clean Water Act and National Pollutant Discharge Elimination System (NPDES) permitting, which sets effluent limits to protect receiving waters. The treated effluent is discharged into local waterways that drain into the Rio Grande basin, eventually reaching the Gulf of Mexico. The plant plays a key role in protecting the region's water quality, supporting downstream ecosystems and agricultural uses in the semi-arid San Luis Valley.

The plant discharges into tributaries of the Rio Grande, which flows through Colorado, New Mexico, and Texas before reaching the Gulf of Mexico. This watershed supports diverse aquatic life and provides irrigation water for the San Luis Valley. The region's arid climate makes water quality management critical for both ecological health and human use.