The City's wastewater system provides wastewater collection, treatment, and disposal for areas within the City Limits and the UGA boundary.
The City's wastewater system consists of two wastewater treatment plants,a network of tributaries, a collection of Lift Stations and pressurized mains, and a Central Operations Facility (COF).
The two Wastewater Treatment Plants (WWTP) are owned and operated by the City of Moses Lake. The Dunes WWTP is a 4.4 million gallon per day Biolac Activated Sludge Plant which presently serves a population of approximately 22,720. The Larson WWTP is a .75 million gallon per day Biolac Activated Sludge Plant which serves an estimated population of 3,000.
The Dunes WWTP is located at 1801 Road K SE. The Larson WWTP is located at 6691 Randolph Road. Both plants are open for guided tours. Please contact our office to reserve a time for your group to tour our facilities.
Plant Technical Specifics
Fats, Oils, and Grease (FOG)
Whom do I call with questions on my sewer bill?
What do I do if my sewer backs up?
Wastewater Division Supervisor
Wastewater Division Foreman
1303 W. Lakeside Dr.
P.O. Box 1579
Moses Lake, WA 98837
Ph: (509) 764-3966*
Fx: (509) 764-3971
Monday - Friday (
7:30 am – 4:00 pm
*In case of a wastewater-related emergency after hours, on weekends or holidays, call MACC Dispatch at (509) 762-1160.
Public Works Calendar
WA State Dept. of Ecology - Wastewater Treatment
Water Environmental Federation
401 S. Balsam | P.O. Box 1579
Moses Lake, WA 98837 | Ph: (509) 764-3701
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