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 20,640. 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
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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