Skip to main content
King County logo

Frequently asked questions

A legal lot is a parcel of land developed through laws in effect at the time of the original subdivision. The criteria to determine the legal status of a lot is specified in section 19A.08.070 of Title19A of the King County Code (KCC), which is online at

The determination of legal lot status is made by Permitting Department staff. If a parcel of land is determined not to have been created legally, the owner may be eligible to apply for building or other permits if the criteria for determining innocent purchaser status (see innocent purchaser form in PDF* (91KB) or fill-in MS Word* (111KB) format), per KCC 19A.08.090, is met to the satisfaction of Permitting Department staff. To speak with a Permitting Department staff member on this subject, call Permitting Department customer service at 206-296-6600. Hours and Locations

A buildable lot is a lot that contains a building site, as defined in KCC 19A.04.060. One of the criteria noted within County Code is that a building site must contain a minimum lot area for construction. Having a lot that is "buildable" still does not necessarily mean that a dwelling unit may be constructed. While a lot may meet the criteria for being "buildable," other approvals such as Public Health (for septic systems) are required before a building permit can be issued.

A taxable lot is a parcel which appears on the King County Assessor's map and has been assigned a tax parcel number by the Assessor. Tax parcel numbers are assigned for billing purposes. A tax parcel number is not necessarily an indication that the lot was legally created.

Properties are zoned within communities to ensure that different types of development are properly situated relative to each other and that there are adequate setbacks, open space, parking, and landscaping for each type of development.

Zoning within King County is divided into two general land use categories:

  • Residential
  • Commercial / Industrial.

Residentially zoned property in unincorporated King County may be either rural area (RA) or urban residential (R). The number of dwelling units allowed per acre is reflected by the number associated with the zone. For example, a property that is zoned R-4 is Urban Residential and has a base density of 4 dwelling units per acre.

Other base zoning code abbreviations and general information are online at

Zoning also determines the setbacks, height restrictions and impervious surface limitations for each property.

More information about property in unincorporated King County can be found using the Density and Dimension charts in Chapter 21A.12 (pdf) of the King County Code.

Please also refer to several Permitting Department customer information bulletins about the Zoning Code.

After determining the zoning and lot size, setback information for property in unincorporated King County can be found on the Density and Dimension charts in Chapter 21A.12 (pdf) of the King County Code. Footnotes relate to the corresponding text and must be taken into consideration when determining development conditions and allowances. For example, property that is zoned RA-10 but is less that one acre will have the setback listed under R-4.

In addition to setback information, this chapter also identifies the number of dwelling units per acre, minimum lot size, and height restrictions as found in the matrix table under each specific zoning designation.

Please also refer to Permitting Department Customer Information Bulletin #17A, Zoning Code: Overview and Summary (PDF*, 125KB).

By knowing the zoning of the property and its size (in acres), customers can determine if a lot can be subdivided.

The Density and Dimension charts in Chapter 21A.12 (pdf) of the King County Code) will be consulted to determine the base density of property (dwelling units allowed per acre) and the minimum lot area required. For example, property in unincorporated King County zoned R-4 and one acre in size can be divided into 4 lots [43,560 square feet (one acre) / 4 (base density per acre) = 10,890 square feet per lot].

Lots that are in the Urban Residential zone must currently have sewer service available in order to subdivide. Note also that proposed subdivisions require a pre-application meeting.

Development on a specific property is determined by its zoning. All issues pertaining to land uses for property in unincorporated King County can be researched by referencing Permitted Uses in Chapter 21A.08 (pdf) of the King County Code.

For additional assistance using this table, please refer to Permitting Department Bulletin 18A, Zoning Code - Permitted Use Tables (PDF*, 159KB).

Espresso Stands are identified under Eating and Drinking Places in the Permitted Uses table in Chapter 21A.08 of the King County Code.   Accordingly, in unincorporated King County, to locate an espresso stand in a residential zone, a Conditional Use Permit, the process for which includes public notice, must first be secured.

Prospective applicants for a Conditional Use Permit (CUP) may want to review KCC 21A.08.070 and 21A.44 Chapter 21A.08 of the King County Code to see if your proposal can meet the requirements outlined for a CUP.  Customers requiring additional information should call the Permitting Department Customer Information Line at 206-296-6600.

In unincorporated King County, espresso stands are permitted outright in Community Business, Regional Business, Office, or Industrial zones.  However, a building permit from the Permitting Department is required and review from Seattle-King County Public Health may also be required.

To determine if an Accessory Dwelling Unit (ADU, also referred to as a mother-in-law apartment) is allowed on a given parcel, customers must know the zoning and lot size.

Generally, however, in unincorporated King County, accessory dwelling units are allowed in all zones except Mineral (M) and Industrial (I), provided that certain conditions are met. Please reference section 21A.08.030(B)(7)(a) in Chapter 21A.08 (PDF*) of the King County Code.

ADUs differ from accessory living quarters in that an ADU is allowed to have a kitchen or kitchen facilities as defined under KCC 21A.06.0662 in Chapter 21A.06 (PDF*) of the King County Code.

The location of property records depends on record type and date.

Please refer to the Permitting Department Records Center for detailed information about locating building plans as well as building permit records.

The Permitting Department Records Center maintains records only for unincorporated King County. However, some records for properties that are annexed or incorporated into a city subsequent to finalization of a King County permit are available at the Permitting Department.

Records for property located within city limits generally require contacting the city (external link) directly.

The following building plans for unincorporated King County are available at the Permitting Department:

  • Residential house plans from only 1987 to present
  • Commercial plans from only 1970 to present.

For a records request form and more information, see the Permitting Department Records Center.

Customers with illegally-built structures on property in unincorporated King County may apply for an Already Built Construction (ABC) permit through the Permitting Department Permit Center. Please contact Code Enforcement at 206-296-6680.

Depending on the quality of construction, alterations to the structure may be required to comply with County Codes. The time period during which the structure was built may be taken into consideration during permit review.

In certain situations, the King County Department of Permitting and Environmental Review (Permitting) may recognize the use of RCW 58.04 (Revised Code of Washington) as a method of resolving boundary problems with or without a court order or the use of a Boundary Line Adjustment (BLA). However, we do not recognize agreements using this process for purposes that it was not intended to be used for.

The Permitting Department concern is that the option for using this process must be limited to situations where "a point or line determining the boundary between two or more parcels of real property cannot be identified from the existing public record, monuments, and landmarks, or is in dispute" (excerpt from RCW 58.04.007, emphasized).

Therefore, when this process is used, the Permitting department requires that the paperwork be submitted to the Permitting Department prior to recording, so that Permitting staff can perform an expedited review to assure that the Boundary Line Adjustment process is not circumvented.

The process that we use to perform this review is the Legal Lot Status Review process (estimated permit fees are available).

If the process defined in RCW 58.04 is found to be an acceptable method to use for establishing the new boundary line location, then the Permitting Department will provide a letter to the Assessor's Office asking that they recognize each new lot configuration as a legal lot, once the proper documentation is recorded.

If the process defined in RCW 58.04 is found not to be an acceptable method to use for establishing the new boundary line location, then the Permitting Department will deny the request for Legal Lot Status. A Boundary Line Adjustment application would then need to be submitted to the Permitting Department for approval in order to adjust the boundary lines.

*Note: To view PDFs, free software from Adobe is required. Word documents require Microsoft software. For assistance, see helpful hints.

To request this information in alternate formats for people with disabilities, call 206-296-6600 or TTY Relay: 711.