The City's wastewater system provides wastewater collection, treatment, and disposal for areas located within City Limits and the UGA boundary.
The City's wastewater system consists of one wastewater treatment plant, a collection of Lift Stations and sewer mains, and an operations facility. The WWTP includes pump station, headworks, aerated sludge, sludge handling, UV disinfection, and rapid infiltration.
The Wastewater Treatment Plant (WWTP) are owned and operated by the City of Mattawa. The WWTP is a 600 thousand gallon per day(0.6 MGD)) Biolac Actiated Sludge Plant which presently serves a population of approximately 5,000 with peaks during the summer months.