Repair on a wastewater maintenance hole

The Wastewater Division of Public Works operates, maintains, and repairs 123 miles of wastewater (sewer) mains, over 3,600 maintenance holes, and six wastewater pump stations. The pump stations convey wastewater to King County's Wastewater Treatment Plants.

The Wastewater Division maintains the City's wastewater mains by performing cleaning, ensuring root removal, and conducting video inspections of the sewer main lines. They also maintain the wastewater maintenance holes through cleaning and infiltration and structural repairs. The photo above is a structural repair done by maintenance crews during the summer of 2019. They are also responsible for keeping Kirkland's six wastewater pump stations operating continuously.

Wastewater is the used water that enters the wastewater system via sinks, toilets, showers, washing machines, drains, and other fixtures. It is mostly water but also contains phosphorous, nitrogen, fats, oils, grease, pathogens, and solids. Kirkland’s wastewater system is separate from the stormwater system, which captures water through storm drains and the natural environment. Stormwater does not go to a treatment plant like wastewater; it travels into our streams, rivers, and finally into Lake Washington.

There are two sewer districts within the city limits of Kirkland. The Northshore Utility District provides wastewater service to the northern, more recently annexed part of the City while Kirkland Public Works provides service to the southern portion. The Northshore Utility District can be reached at 425-398-4400. This map shows the approximate boundaries of the different water and sewer districts(PDF, 10MB) that serve Kirkland.

There are 11,202 private side sewer connections to the City's main. If you would like the City to check for an as-built for a particular property within Kirkland's sewer area, use the Our Kirkland service portal or call 425-587-3800.

Public and private responsibility


Within the City of Kirkland's sewer district, the city operates and maintains the public sewer infrastructure including public sewer mains. The customer owns and maintains the private side sewer pipe that begins at the public sewer main and connects to the house/building. This includes the entire side sewer pipe on private property and in the public right-of-way. 

Plumbing on private property is the property owner's responsibility, including but not limited to plumbing fixtures such as toilets, sinks, bathtubs, and showers, drains, sewer cleanouts, and pipes. 

The city may have a record (as-built) of where a private side sewer is located. Please call Public Works Engineering and Development at 425-587-3800 to determine if the city has this information. 


Keep your drains fat-free!

The City of Kirkland's Fats, Oils, Grease (FOG) page explains why allowing fats, oils, and grease down the drain is an expensive problem, an environmental hazard, and a public heath issue. It contains information and tips for residents, restaurants, and businesses. 

You can recycle your used cooking oil by bringing it to the collection tank at the North Kirkland Community Center.

Don't flush trash

From King County: Wipes, paper towels, and other "unflushables" can create a sewer backup in your home. Flush only toilet paper and protect your home, the sewer system, and the environment.

 Only flush toilet paper - everything else in the trash even if labeled as flushable

Only flush toilet paper - everything else in the trash even if labeled as flushable

Sewer rates

Current City of Kirkland sewer rates can be found on this page Water, Sewer, and Garbage Rates

Septic systems

Public Health - Seattle & King County's On-site Sewer System (OSS) Program provides educational, advisory, and permitting services for owners of septic systems.

King County Regional Wastewater Services Plan

Since 1958, King County has protected water quality in the Puget Sound region by providing wastewater treatment services to King, Pierce, and Snohomish counties. Visit the King County Regional Wastewater Services Plan page to learn more.

Industrial waste

All dischargers that generate and dispose of industrial wastewater to the sewer system must get approval from the King County Industrial Waste Program prior to discharging. 

Locate markings and digging

Washington State Law requires that underground utilities be marked before you dig. The City of Kirkland marks city utilities in the public right-of-way only. Puget Sound Energy, Comcast, Ziply, Northshore Utility District, Woodinville Water, and others have underground assets in Kirkland as well. 

Some underground utilities belong to you, such as your side sewer, water service line, and private storm water system. The city does not mark underground utilities on private property. You will need to hire a private company to mark your personal property. 

The paint used for locate markings is designed to wear away in time. The city does not remove it. The color of the paint indicates what type of asset has been marked. 

The Washington Utility Notification Center and Washington811.com have more information about marking underground utilities. Call 811 before you dig.