The City of Everett’s 1st sewers were constructed in 1890, 3 years before Everett was incorporated. In 1897, the construction of the citywide system began in north Everett. This north portion of the system is combined, carrying stormwater and sanitary sewage to the Everett Water Pollution Control Facility (EWPCF). With population growth, the system expanded to the south. The south portion of the system is sanitary sewage only.
Today, the wastewater system serves 165,000 people, conveying sewage through approximately 345 miles of sewer mains, interceptors, laterals, and 31 lift stations to the EWPCF. In addition to the population of Everett, the EWPCF also treats a portion of the sewage from 3 neighboring sewer systems: Mukilteo Water and Wastewater District, Alderwood Water and Wastewater District, and Silver Lake Water and Sewer District. The system plays a vital role in protecting public health. It also protects rivers, lakes, and streams from pollutants and minimizes harmful impacts to the natural environment.
Two Parallel Wastewater Treatment Systems
The EWPCF is located on Smith Island in north Everett. It has 2 parallel wastewater treatment systems, which provide secondary (biological) treatment with disinfection. The trickling filter/solids contact (TF/SC) system is a mechanical plant, which treats up to 25 million gallons per day (MGD). The aeration / oxidation ponds, or lagoon system, treats the wastewater flows not treated and discharged by the TF/SC plant and provides storage capacity for storm flows from the combined sewage system. Discharge of effluent from the 2 treatment systems is through 2 separate outfalls.
Discharge & Expansion
The TF/SC mechanical plant discharges to a marine deep-water outfall in Port Gardner Bay shared with the City of Marysville. The lagoon system discharges to the Snohomish River. A plant expansion completed in 2015 increased the EWPCF total hydraulic capacity to 40.3 MGD.
Each person contributes about 50 to 100 gallons of used water each day to the wastewater flow. Sewer lines carry wastewater from