PCRWRD Mount Lemmon WWTF - Pima County, Arizona Wastewater Treatment Plant

PCRWRD Mount Lemmon WWTF is a municipal wastewater treatment facility located in Pima County, Arizona, United States. The plant serves a small population of 353 residents in the Mount Lemmon area, providing essential wastewater management for this mountainous community. The facility operates at the secondary treatment level, which is standard for small communities in the United States under the Clean Water Act. With a designed capacity of 56.78 units and an average daily discharge of 11.36 units, the plant has ample capacity to handle current flows. As a US facility, it operates under the National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits to protect water quality. The plant's treated effluent is discharged into local waterways that drain into the Santa Cruz River watershed, ultimately flowing south toward the Gulf of California. The receiving waters support diverse aquatic life and are important for regional water resources in the arid Southwest.

The plant discharges into streams within the Santa Cruz River basin, which flows through southern Arizona and into Mexico. This watershed supports riparian habitats in an otherwise arid region, providing critical corridors for migratory birds and native fish species. The treated effluent contributes to base flow in ephemeral streams, sustaining aquatic ecosystems downstream.