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Annexation Methods by Cities and Towns

This page provides a general overview of the various possible methods of annexing territory by cities and towns in Washington State.

It is part of MRSC's series on Annexation in Washington State.


The methods by which cities and towns can annex territory are governed strictly by state law, and they vary somewhat by city classification. The methods of annexation by code cities are in chapter 35A.14 RCW, while the methods of annexation by non-code cities are in chapter 35.13 RCW.

Note that cities and towns located in counties that plan under the Growth Management Act may annex only property that is located within their designated urban growth areas.

Of all the methods of annexation available, the sixty percent petition method is by far the most frequently used. Cities have found the election method to be extremely cumbersome. Because of this and the expense of conducting an election, annexation elections are infrequent. Statutes authorizing summary annexations for municipal purposes are much more straightforward, but may be utilized only when a legitimate municipal reason for annexation can be shown, such as the use of the annexed land for a city park or water tower. Finally, the statutes authorizing the annexation of federal areas are of very limited application.

Detailed descriptions of all annexation methods are available in our publication Annexation by Washington Cities and Towns, both for code cities and non-code cities (first and second class cities, and towns).

For a general overview of each of the methods of annexation, including links to sample documents for each method, see our summaries below:

Note that the sample documents under each method are organized according to city classification, as the procedures vary somewhat.

Sixty Percent Petition Method (Direct Petition Method)

The sixty percent petition method, or direct petition method, is the most commonly used method of annexation by cities and towns in Washington State. It requires the signatures of property owners representing 60% of the assessed value of the area proposed for annexation.

The sixty percent petition method is sometimes referred to as the "old" petition method of annexation. In 2002, the Washington State Supreme Court invalidated this method on constitutional grounds in Grant County Fire Protection Dist. v. Moses Lake (2002). Not long afterward, the same court reversed itself and determined this method was valid in Grant County Fire Protection Dist. v. Moses Lake (2004). During the period it had been deemed unconstitutional, the legislature adopted a new alternative petition method that was consistent with the court’s 2002 decision. Both the “old” sixty percent petition method and the “new” alternative petition method continue to be options today.

The sixty percent petition method is codified at:

Examples of Initiating Notices (Code & Non-Code)

The sixty percent petition method is initiated by an initiating notice signed by 10% of the property owners (RCW 35A.14.120).

Code Cities

Non-Code City

Examples of Annexation Petitions (Code Cities)

If the city council accepts the initial annexation proposal, the initiating parties may draft and circulate a petition for signatures.

Examples of Ordinances (Code & Non-Code)

Code Cities

Non-Code Cities

Alternative Petition Method

This method was adopted by the Legislature during the period (2002-04) that the traditional sixty percent petition method had been declared unconstitutional by the state Supreme Court. It requires the support of property owners representing a majority of the area proposed for annexation and of a majority of the voters in the area.

The method is codified at:

Examples of Notices and Petitions (Code & Non-Code)

Code Cities

Non-Code City

Examples of Resolutions and Ordinances (Code & Non-Code)

Code Cities

Non-Code City

  • Yakima Ordinance No. 2019-014 (2019) – Ordinance established pursuant to RCW 35.13.420(2), which states that "[i]f no residents exist within the area proposed for annexation, the petition must be signed by the owners of a majority of the acreage for which annexation is petitioned."

Examples of Procedures and Application (Non-Code City)

Election Method (Initiated by Petition or by Resolution)

The election method requires approval of the voters in the proposed annexation area. Election method annexations may be initiated either by a petition signed by a percentage of the voters living in the area to be annexed who voted in the last election (10% if a code city, or 20% if a non-code city), or by city council resolution. Both election methods (initiated by petition or resolution) are nearly identical except for the first few steps. Cities have found the election method to be cumbersome and expensive. Because of this, annexation elections are much less common than the petition methods.

The election method is codified as follows:

Note: If the election method of annexation is to be used, a word of caution is necessary. Since a ballot proposition is involved, the public information program must be tailored to comply with RCW 42.17A.555, which generally prohibits the use of public funds in promoting or opposing a ballot measure. See also MRSC’s topic page Use of Public Facilities in Election Campaigns.

In short, cities and towns should not publish promotional material urging a favorable vote in an annexation election. City employees should not use city facilities and resources to actively attempt to influence voter response. However, a distinction may be drawn between promoting an annexation and merely providing factual information directed at enabling voters to make their own decisions based on factual data, rather than uninformed speculation. The annexation statutes specifically authorize a city or town to “provide factual public information on the effects of a pending annexation.” See RCW 35.13.350, 35.21.890, 35A.14.550, and WAC 390-05-271, 390-05-273.

If a private citizen group is involved, any legal ambiguities as to the information that can be provided may be avoided when the citizens group, rather than the city, prepares, finances, publishes, and distributes the annexation information pamphlets. Citizen groups may not only provide factual information, but also advocate positions. Any such group would be well advised to check with the Public Disclosure Commission early in its formation stages, to learn whether any campaign financing information or forms will be expected of the committee.

Examples of Resolutions and Ordinances Calling for Election (Code Cities)

  • Bothell
  • Kirkland
    • Resolution No. 4751 (2009) - Calling for the annexation by election of certain territory
    • Resolution No. 4763 (2009) - Calling for a special election to be held in conjunction with the general election for the purpose of placing on the ballot a proposition concerning the annexation of certain territory
    • Resolution No. 4791 (2009) - Expressing the Council’s intent to accept the annexation of certain Territory
    • Ordinance No. 4196 (2009) - Related to zoning and land use and preparing zoning regulations
  • Sammamish
    • Resolution No. R2014-602 (2014) – Declaring the city’s intent to annex an unincorporated area of King County and calling for an election to be held submitting to the voters within the area of the proposal for annexation
    • Resolution No. R2015-615 (2015) – Requesting that the King County director of elections hold a special election for the purpose of placing on the ballot a proposition concerning the annexation of certain property
    • Ordinance No. O2015-393 (2015) – Annexing certain property after election

Unincorporated Islands Method

This method enables the annexation of territory that is wholly or mostly surrounded by incorporated territory and is a much shorter process than required for the petition and election methods of annexation. This method is available to cities planning under the Growth Management Act (GMA), and the territory must be within a designated urban growth area. The criteria for annexing these “unincorporated islands” differs somewhat between code and non-code cities. A city council may initiate annexation under this method by resolution.

Per RCW 35A.14.295, a code city may annex an area under the unincorporated island method of annexation if:

  • the area is less than 175 acres and all its boundaries are contiguous to the city (i.e., it is entirely surrounded by the city); or
  • the area is of any size and has at least 80% of its boundaries contiguous to the city, it contains residential property owners, and it is within the same county and urban growth area as the city, and the code city is required to plan under the Growth Management Act (GMA).

Annexations under this method are subject to potential referendum (RCW 35A.14.297-.299).

The authority provided to non-code cities under this method is more limited than for code cities. Per RCW 35.13.182, an area may be annexed by a non-code city under this method if the city was planning under the GMA as of June 30, 1994, the area contains residential property owners, the area is within the same county and urban growth area of the city, and:

  • the area is less than 100 acres and has at least 80% of its boundaries contiguous to the city; or
  • the area is of any size, has at least 80% of its boundaries contiguous to the city, and it existed before June 30, 1994.

Annexations under this method by non-code cities are also subject to potential referendum (RCW 35.13.1821).

Examples of Resolutions and Ordinances (Code Cities)

Unincorporated Island-Interlocal Agreement Method

This method provides an "alternative" method of annexing islands of unincorporated territory through use of interlocal agreements. However, this "island-interlocal" method of annexation is only available to cities and towns located in counties that are subject to the "buildable lands" review and evaluation program under the Growth Management Act (GMA).

These counties are: Clark, King, Kitsap, Pierce, Snohomish, Thurston, and Whatcom.

This unincorporated island-interlocal agreement method is codified in:

Unlike the existing method of annexing unincorporated "islands" of territory, which requires the proposed annexation area to have at least 80% of its boundaries contiguous to a single city (RCW 35.13.182 and 35A.14.295), the proposed annexation area under this "island-interlocal" method need have only 60% of its boundaries contiguous to a city or to more than one city. As with all annexations in counties subject to the GMA, the proposed annexation area must be within an urban growth area (UGA).

Annexations under this method are subject to potential referendum.

Examples of Ordinances and Interlocal Agreements (Code Cities)

Municipal Purpose Method

This method allows the annexation of property that is to be used for a "municipal purpose" and is accomplished by city council action alone. Notably, it can be used to annex territory that is not contiguous to existing boundaries.

Territory can be annexed by this method:

  • For code cities, only if it is owned by the city (RCW 35A.14.300).
  • For non-code cities, if the territory is either owned by the city or if all of the property owners in the territory give their written consent to the annexation (RCW 35.13.180).

Examples of Ordinances (Code Cities)

Examples of Ordinances (Non-Code Cities)

Interlocal Agreement Method (Code Cities ONLY)

In March 2020, the state legislature passed SB 5522, amending Chapter 35A.14 RCW to create a new method of annexation for code cities. Under this method (RCW 35A.14.296), a code city may annex unincorporated territory pursuant to an interlocal agreement between the city and county, subject to the following requirements.

Notice of Annexation to Impacted Special Purpose Districts/City

  • The city must provide written notice to the governing authorities of the following impacted special purpose districts and adjacent city (if applicable):
    • Fire protection districts, regional fire protection service authorities, water-sewer districts, and transportation benefit districts within the proposed annexation area;
    • Any city adjacent to the proposed annexation area where the sole access or majority of egress and ingress of the area is served by the transportation network of the impacted city.
  • The impacted districts or city will have 30 days from the date of such notice to notify the code city whether it would like to be a party to the interlocal agreement with the city and county. If timely notice is provided, the notifying district(s) and/or city must be included as a party to the agreement.
  • Any impacted district or city may disagree with the annexation, in which case, the annexation may not proceed using this new method.

Public Hearing

  • A public hearing must be held by each legislative body, either jointly or separately, before an interlocal agreement is executed.
  • Notice of availability of the agreement must be published at least once a week for four weeks prior to the hearing on the city and county website (if available), and in a newspaper of general circulation within both the code city and the territory proposed for annexation. The notice must also indicate if the annexation would provide for assumption of indebtedness or adoption of proposed zoning regulations.

Interlocal Agreement

  • The boundaries and effective date of the annexation are decided jointly and set forth in the interlocal agreement.
  • The date of the public hearing must be set forth in the interlocal agreement.
  • The interlocal agreement must ensure that for a period of five years after the annexation, any residentially-zoned parcels retain their residential zoning, and the area’s minimum gross residential density must not be reduced below the density allowed prior to annexation.
  • An interlocal agreement may be amended to add additional territory.

Annexation Ordinance

  • After the public hearing, the city must adopt an ordinance to effect the annexation. An annexation agreement may include phased annexation of territory. If it does, an ordinance must be adopted at each phase of annexation.
  • A certified copy of the annexation ordinance must be filed with the board of county commissioners of the county in which the annexed property is located.

Interlocal Agreement Method for Annexation of Areas Served by Fire Districts

This is a method of annexation adopted by the legislature in 2009 that may be employed where a city is proposing to annex territory within one or more fire protection districts (RCW 35A.14.480 for code cities and RCW 35.13.238 for non-code cities). Under this method, a city, the county in which the city is located, and a fire district or districts may enter into an interlocal agreement that describes the annexation area and the goals of the agreement, including such matters as:

  • Transfer of revenues and assets between the fire protection district(s) and the city
  • Impact of annexation on the level of fire protection and emergency medical service in both the unincorporated and incorporated area
  • Community involvement in the process
  • Revenue sharing, if any

If only the city and the county reach agreement on the enumerated goals, the annexation may still proceed.

Annexations under this method are subject to potential referendum.

Examples of Interlocal Agreements (Code Cities)

Examples of Interlocal Agreements (Non-Code Cities)

Annexation of Federal Areas

The procedures for annexing land that is owned by the federal government are found in:

Examples of Ordinances (Code Cities)

Boundary Line Adjustments to Shift Boundaries Associated with Rights-of-Way or Split Parcels

State law provides a process for adjusting existing or proposed city boundary lines to avoid a situation where a common boundary line is or would be located within a right-of-way of a public street, road, or highway (RCW 35.13.300-.340). The process also applies to the situation where two cities are separated or would be separated only by the right-of-way of a public street, road, or highway, other than where a boundary line runs from one edge to the other edge of the right-of way (RCW 35.13.300). The process is available to all cities and towns, including code cities.

Boundary adjustments can also be made where a portion of a parcel of land is located partially within and partially without city boundaries (or a parcel is split between two cities), where the property owner requests the adjustment and the process at RCW 35.13.340 is followed.

Examples of Resolutions

Recommended Resources

  • Annexation by Washington Cities and Towns – This publication outlines the pro and con arguments for annexation, the consequences of annexation, reviews in detail the methods for annexation, and discusses the role of boundary review boards in the annexation process.

Last Modified: February 23, 2024