Wastewater (Sewer)

Sewer/Stormwater Division provides operation and maintenance of the wastewater treatment plant with Streets Division staff performing maintenance activities for the sewer collection and stormwater drainage systems.  Division funds are used for upgrading and maintaining the stormwater draining system, the sanitary sewer collection system for delivery to the wastewater treatment plant, and the wastewater treatment plant for safe and convenient disposal of human and manufactured liquid wastes.

Sewer system consists of:

  • 55 miles of gravity flow collection piping
    • 6-inches to 48-inches
    • PVC, Concrete, Clay, Asbestos Cement, Ductile Iron, Cast Iron materials
    • Epoxy slip lines
  • 5 lift stations
  • Wastewater Treatment Plant
    • 1.95 million gallons per day: dry weather
    • 4.65 million gallons per day: wet weather
    • National Pollution Discharge Elimination System permit
      • 5.50 million gallons per day
      • Discharge to Umatilla River
    • Membrane thickener
      • Use retired membranes from water treatment plant
      • Convert to membrane bioreactor in 2017 / 2019
  • Wholesale customers
    • Confederated Tribes of the Umatilla Indian Reservation
    • Rieth Sanitary Sewer District

Stormwater system consists of:

  • 30 miles of gravity drainage piping
    • 10-inches to 54-inches
    • PVC, Concrete, Steel, Ductile Iron, Cast Iron materials
  • 18 discharge locations
    • Umatilla River
    • McKay Creek
    • Tutuilla Creek
    • Nelson Creek

Operating budget for this Division is about $3,800,000 annually, with $800,000 for annual capital outlay projects and $1,200,000 transferred to Capital Reserve for future wastewater treatment plant upgrades.  There are 6 full-time employees and 1 part-time employee equivalent providing these services.

What is Wastewater Treatment?

Wastewater (sewage) is carried through underground pipes, known as the collection system, to the Wastewater Treatment Plant. Wastewater Treatment is the physical, chemical and biological process that turns that dirty water into clean water.  The treated water is returned to the Umatilla River. If you or a group would like a tour of the City's Wastewater Treatment Plant, contact Mark Milne at 541-276-3372 to make arrangements.