College Place's wastewater treatment facility is owned by the City and operated and managed under a contract with Jacobs.   The facility serves a population of approximately 9,775 residents.  Built in 2001, the College Place Wastewater Treatment Plant is a 2-million-gallon-per-day complete-mix activated sludge /sequencing batch reactor plant.  Wastewater is delivered to the plant by  a collection system.   Currently the facility treats approximately 950,000-gallons-per-day.


The plant is located on 430 Owens Rd and is open for guided tours. Please contact our office to reserve a time for your group to tour our facility.  The City's wastewater system is separated into collection and treatment.

A Department of Ecology Permit Report On Our Plant is located here. 


Wastewater Treatment Plant Facility Plan

Adopted General Sewer Plan

Draft Port of Walla Walla/City of College Place/City of Walla Walla WWTP Consolidation Report 

Sewer Backup Information

To report a sewer backup during normal business hours, please contact Mr. Paul Olson  - Project Manager for Jacobs: (509)-529-2859 or  If this is an emergency after hours, please call the 509-527-1960.

Wastewater System Ban List

Wastewater treatment is a biological process. Never dispose any of the following down your (street) storm drain or sewer (toilet, sink or any drain in the house) to the wastewater/sewer system:    

  • Pharmaceuticals
  • Excessive amounts of bath or body oils
  • Water softener backwash
  • Household cleaners, especially floor wax and rug cleaners
  • Chlorine bleach, chlorides, and pool or spa products
  • Pesticides, herbicides, agricultural chemicals, or fertilizer
  • Flammable or toxic products