Mesa Northwest Water Reclamation Plant (WRP) - Mesa, Arizona Wastewater Treatment

Mesa Northwest Water Reclamation Plant (WRP) is a major wastewater treatment facility located in Mesa, Arizona, United States. Serving a population of approximately 120,640, it plays a critical role in managing the city's wastewater and supporting water reuse in the arid Southwest. As a plant of this scale in the United States, it operates under the National Pollutant Discharge Elimination System (NPDES) permit program, established by the Clean Water Act. This regulatory framework requires secondary treatment as a minimum, with additional nutrient removal or advanced treatment often mandated for sensitive watersheds. The plant's treatment processes are designed to meet stringent permit limits to protect public health and the environment. The treated effluent from Mesa Northwest WRP is discharged into the local watershed, which ultimately drains into the Salt River and then the Gila River, a tributary of the Colorado River. This water is vital for downstream ecosystems, agriculture, and urban water supplies in the arid region. The plant's reclamation efforts contribute to water conservation and the sustainability of the Colorado River Basin.

The plant discharges into the Salt River watershed, which flows into the Gila River and eventually the Colorado River. This arid region relies heavily on reclaimed water to support riparian habitats, agricultural irrigation, and municipal water supplies. The Colorado River Basin is a critical water source for millions of people and diverse ecosystems in the southwestern United States.