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A. General. One accessory dwelling unit is permitted as subordinate to a single-family dwelling provided the following criteria are met:

1. Accessory dwelling units may not be subdivided or otherwise segregated in ownership from the primary residence structure;

2. Either the primary residence or the accessory dwelling unit must be occupied by an owner of the property that meets the definition of owner occupancy in LUC 20.50.038;

3. The accessory dwelling unit shall contain not less than 300 square feet and not more than 800 square feet, excluding any related garage area; provided, if the accessory unit is completely located on a single floor, the Director may allow increased size in order to efficiently use all floor area, so long as all other standards set forth in this section are met;

4. The square footage of the accessory dwelling unit, excluding any garage area, shall not exceed 40 percent of the total square footage of the primary residence and accessory dwelling unit combined, excluding any garage area;

5. There shall be one off-street parking space provided for the accessory dwelling unit, which is in addition to any off-street spaces required for the primary residence, except when the property has frequent transit service as provided in LUC 20.20.590.L.1;

6. The construction of a second entry door facing a street front for entrance into an accessory unit is prohibited; new entrances not facing a street front are permitted on the sides and rear of a house, or on the front side of a house facing a street where no other entry door exists; provided, that existing single-family structures with two or more entry doors facing a street shall not be prohibited from using one of those doors to access the accessory unit; and

7. The accessory dwelling unit shall meet all technical code standards, BCC Title 23, including building, electrical, fire, and plumbing code requirements.

B. Location. Accessory dwelling units shall not be permitted in structures detached from the primary residence, including but not limited to guest cottages, detached garages, or workshops.

C. Limitations. A site may not contain both an accessory dwelling unit and a business subject to the regulations in Part 20.30N LUC for a Home Occupation Permit.

D. Affordable Housing. The creation of an accessory dwelling unit shall not satisfy the affordable housing requirements in LUC 20.20.128.

E. Inspection and Registration.

1. Any property owner seeking to establish an accessory dwelling unit shall apply to register the unit with the Development Services Department.

2. The property owner shall file a completed registration application form affirming that at least one owner will occupy the primary residence or the accessory unit, and the property owner shall agree to the limits on total number of residents and all other standards provided in this section. The registration application shall include a requirement for mailing labels for all owners of property lying within 500 feet of the site.

3. After receipt of a complete application form and prior to approval of any accessory dwelling unit, the Director shall inspect the property to confirm that minimum and maximum size limits are met, required parking is provided, design limitations regarding front entrances are met, and technical code standards are met.

4. The registration form or other form as required by the Director shall be filed as a deed restriction with the King County Department of Records and Elections to indicate the presence of the accessory dwelling unit, the requirement of owner occupancy, and other standards for maintaining the unit as described above.

5. The Director shall report annually to the City Council on accessory dwelling unit registration, number of units and distribution throughout the City, average size of units, and number and type of complaint- and enforcement-related actions.

6. After approval, the Director shall provide notice of the registration of the accessory unit to owners of property within 500 feet of the registered site. The notice shall state that the unit complies with the standards of this section, shall describe the requirements for maintaining the unit, and shall explain how to obtain general information and how to request inspections.

7. Cancellation of the accessory unit’s registration may be accomplished by the owner filing a certificate with the Director for recording at the King County Department of Records and Elections, or may occur as a result of enforcement action. The cancellation certificate will confirm that the residence has reverted to use as a single dwelling. (Ord. 6616, 11-15-21, § 1; Ord. 6589, 7-19-21, § 1; Ord. 6575, 4-26-21, § 1; Ord. 6567, 2-16-21, §§ 1, 2; Ord. 5718, 2-20-07, §§ 1, 2; Ord. 5089, 8-3-98, § 8; Ord. 4498, 3-15-93, § 2)