Wastewater / Sewer

Wastewater / Sewer MaintenanceWastewater (Sewer) Maintenance


The City of Redmond Wastewater Maintenance Division maintains and operates the wastewater (sewer) system to meet the needs of existing and future customers. The wastewater system serves a residential population of over 60,000 within the city limits and approximately 3,500 residential households in the Novelty Hill area.

City staff maintain the wastewater system in a manner which protects the public investment, protects the environment and human health, ensures compliance with state and federal mandates, and ensures that reliable service is available to all customers of the City utility system.

Wastewater staff provide information to commercial customers and residents pertaining to treatment and reduction of grease and industrial discharges to the wastewater system to ensure compliance with pretreatment standards. Wastewater Division staff also collaborate with Utility Engineering staff on long-range system development and comprehensive planning, the capital facility program, and feasibility studies.

Contact: 425-556-2800


The first wastewater system in Redmond was constructed in 1958 in conjunction with the Redmond sewage treatment lagoon. This original system served downtown Redmond and residential areas to the north. The Redmond sewage treatment lagoon was operated for six years before it was phased out of service in 1964.

During the 1960s, the wastewater system was extended to the north and south as more areas outside of downtown were developed. In 1968, a Comprehensive Plan for Sanitary Sewers was completed for the City of Redmond as were improvements to the existing wastewater system to serve areas experiencing heavy growth.

The Municipality of Metropolitan Seattle (Metro; now known as King County Wastewater Treatment Division) purchased the pump station at the lagoon and diverted flows to the Lake Hills Sewage Treatment Plant on West Lake Sammamish Boulevard. This system configuration was maintained until the early 1970s, when Metro completed the Northwest Lake Sammamish Interceptor. Redmond flows were then directed into the new interceptor and the treatment plant was abandoned.

Since the Metro facilities’ completion in the early 1970s, the City of Redmond’s wastewater system has expanded to serve most areas within the city limits. What once contained large acreages of land with single homes, served by individual wells and onsite sewage disposal systems, is now a bustling community of new homes on urban sized lots mixed with older established homes on larger lots. These new homes are being served by city infrastructure for their water and wastewater systems.

The growth of commercial and light industrial activity in Redmond has required the expansion of wastewater facilities, most notably in the Willows Road and Southeast Redmond areas.

The City has also expanded wastewater service to the east, beyond city limits, to Novelty Hill. A new Novelty Hill Trunk Sewer replaced the existing undersized Union Hill Trunk and provided gravity service to all of the eastern portions of the Southeast Redmond and Novelty Hill basins.

Redmond’s wastewater system currently consists of a network of mains, trunks, force mains, and pump stations that transport the collected wastewater to King County Wastewater Treatment Division interceptors. Redmond’s wastewater is ultimately transported to the County’s Brightwater Treatment Plant.

What do we find in the sewer?

  1. Coins
  2. Cell phones
  3. Nuts and bolts
  4. Jewelry 
  5. Pagers
  6. Toys
  7. Credit cards
  8. Car keys
  9. Security badges 
  10. Tools 
  11. Coke-a-Cola bottles 
  12. Pad locks 
  13. Glasses 
  14. Clothes
Things we haven’t found: Mutant Ninja Turtles!

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