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Sewer Utilities

This page provides general information about sewer utilities in Washington State, including information on statutes, administration, side sewers, and funding.


Sewer utilities, whether operated by a city, county, or special purpose district, have these common goals;

  • Develop comprehensive sewer plans for sewer systems;
  • Provide for collection, treatment, and disposal of domestic, commercial, and industrial wastewater in accordance with federal and state regulations;
  • Establish rates for collection, treatment, and disposal of wastewater that provide adequate revenue for administration, operation, maintenance of the sewer system;
  • Provide for customer billing services and processes that are fair, equitable and in compliance with accepted accounting principles.

Statutes and State Regulations

Utility Billing and Collection

For information on utility billing – including utility billing procedures, financial assistance programs, property transfers, and collection of delinquent utility accounts – see our pages on Utility Billing.

Sewer Rates

An excellent resource for sewer rates (as well as water and stormwater rates) is AWC's 2018 Utility Rate Survey. This allows you to compare utility rates, rate structures, number of connections, and other characteristics for up to three cities at a time. (This data is only for cities, not counties or special purpose districts.)

Below are selected examples of sewer rate schedules, studies, and RFPs. 

Rate Studies & Schedules



Planning - Comprehensive Sewer/Wastewater Plans

Planning for Sewer/Wastewater Systems

Comprehensive Sewer/Wastewater Plans

Sanitary Sewer Regulations

Below are selected examples of general sanitary sewer regulations.

  • Entiat Municipal Code Ch. 13.10
  • Kent Ordinance No. 4210 (2016) - Repealing and readopting sanitary sewer standards. New topics addressed include fats, oils, and grease (“FOG”) and new enforcement provisions.
  • Shoreline Ordinance No. 780 (2017) - Repealing the city’s water and sewer code and replacing it with a new wastewater utility chapter, as required for city’s assumption of the Ronald Wastewater District

Side Sewers

Side sewers (sometimes known as "building sewers") connect individual buildings to the sewer main. There are no specific statutes or court cases that we are aware of addressing side sewer ownership, but MRSC generally considers side sewers – including the portions within the public right-of-way – to be owned by the private property owners, as side sewers are privately constructed and benefit private property interests rather than the public sewer system as a whole.

As such, side sewer repair and replacement is generally the responsibility of the property owner, as it could potentially be considered a gift of public funds for a public utility to maintain side sewers benefiting private property interests. However, there are exceptions if the private benefit is incidental to the overall public benefit – see AGO 2009 No. 5.

Some jurisdictions opt to maintain the portion of the side sewer within the public right-of-way and only assign responsibility to the property owner for the portion of the side sewer on private property (from the building to the property line). Others hold property owners responsible for the entire side sewer, all the way from the building to the sewer main, including the portion within the public right-of-way (from the property line to the sewer main).

Side sewer maintenance and repair often comes as a surprise to property owners. Repairs can be expensive, and homeowner's insurance usually does not cover the portion of the side sewer between the property line and the sewer main. At least one jurisdiction – Tacoma, see below – requires prospective buyers and sellers to be given a city flyer educating them about side sewers prior to closing.

Below are selected examples of side sewer policies and related documents.

Side Sewer Ownership & Responsibility

  • Bainbridge Island Municipal Code Sec. 13.12.060 - City is responsible for the portion of the side sewer lying within the street right-of-way or easement
  • Ilwaco Municipal Code Sec. 14.06.120 - Property owner must pay all costs related to side sewer installation and connection. Property owner must pay for all side sewer repairs on the property and must pay to fix any blockages within the public ROW that originate on private property.
  • Kitsap County:
    • Code Ch. 13.12 - Distinguishes between "side sewer" (sewer main to property line) and "building sewer" (property line to building)
    • Side Sewer Brochure - Information for property owners about what a side sewer is, how to inspect and maintain it, and how to prevent blockages
  • Spokane County Code Sec. 8.03.1870 - Property owner is responsible for maintenance and repair of entire side sewer, including portion within public ROW.
  • Sumner Municipal Code Sec. 13.16.290 - Building sewer (side sewer) located in public ROW is property of the city and shall be maintained, repaired, and replaced by the public works department. Property owners are responsible for side sewer on their property.

Side Sewer Construction, Maintenance & Regulations

Fats, Oils, and Grease ("FOG")

Fats, oils, and grease (“FOG”) from food preparation can build up within private side sewers and the public sewer main, causing blockages and sewage backups. While FOG may be liquid during food preparation, it can become viscous or solidify after it is dumped down the drain as temperatures and conditions change, so it is important to minimize the amount within the sewer system through regulations and FOG control devices (for commercial/industrial producers) as well as public education programs (for all users including home cooks).



Biosolids are sewage sludge that is a primarily organic, semisolid product resulting from the wastewater treatment process, that can be beneficially recycled and meets all applicable regulatory requirements. The Washington State Department of Ecology Biosolids page provides laws and rules, permitting process, permits and related forms, guidelines, annual reports, FAQs, links to related resources, and contact information. MRSC provides links to some of the local government waste water biosolid programs.

Biosolids Programs

Biosolids References


Cybersecurity is critical for sewer utilities, which must protect vital infrastructure in addition to customer billing information, personal employee information, and important internal documents. For a list of helpful resources, see our Cybersecurity Resources for Local Governments.

Recommended Resources

Below are some useful resources related to public sewer utilities.

In-State/Regional Resources

Out-of-State/National Resources

Last Modified: February 23, 2024