18.56.005   Intent.

This chapter is intended to promote and encourage the creation of accessory dwelling units (ADUs) in a manner that enhances residential neighborhoods in order to meet the city's housing needs and realize the benefits of ADUs to: (1) provide homeowners flexibility in establishing separate living quarters within or adjacent to their homes for the purpose of caring for and providing housing for family members or obtaining rental income; (2) increase the range of housing choices and the supply of accessible and affordable housing units within the city; and (3) ensure that the development of ADUs does not cause unanticipated impacts on the character or stability of single-family neighborhoods.

(Ord. No. 1120, § 3(Exh. A), 3-21-2019)

Editor's note— Ord. No. 1120, § 3(Exh. A), adopted March 21, 2019, set out provisions intended for use as § 18.56.010. For purposes of classification, and at the editor's discretion, these provisions have been included as § 18.56.005.

18.56.010   Definitions.

"Accessory dwelling unit" (ADU) means a smaller, auxiliary dwelling unit located on a lot occupied by a single-family detached dwelling. This unit provides a separate and completely independent dwelling unit with facilities for cooking, sanitation and sleeping, and has a separate and independent entry/exist than one utilized for the primary residence.

"Attached accessory dwelling unit" means an accessory dwelling unit that is attached to or part of the primary single-family housing unit. Examples include converted living space, basements or attics, attached garages, additions, or a combination thereof.

Example of Attached ADUs

"Detached accessory dwelling unit" means an accessory dwelling unit that consists of a building that is separate and detached from the primary single-family housing unit. Examples include converted garages or new standalone construction.

Example Detached ADU

"Dwelling unit" means a residential living unit that provides complete independent living facilities for one or more persons and that includes permanent provisions for living, sleeping, eating, cooking, and sanitation.

(Ord. No. 909, § 2 (Exh. A), 6-18-2009; Ord. No. 1120, § 3(Exh. A), 3-21-2019)

18.56.020   Where authorized.

ADUs shall be permitted within any residential district subject to review and compliance with the standards and requirements of this chapter.

(Ord. No. 909, § 2 (Exh. A), 6-18-2009; Ord. No. 1120, § 3(Exh. A), 3-21-2019)

18.56.030   Performance standards for accessory dwelling units.

A.

Performance Standards. All performance standards, including lot size, minimum yard setbacks and overall building coverage as set forth for the applicable zoning district and in Chapter 18.50, except as modified by this chapter, shall be met with respect to the ADU.

B.

Number. No more than two ADUs shall be permitted in conjunction with the primary dwelling unit on a single lot of record provided that adequate provisions for water and sewerage are met. One attached ADUs may be allowed within the existing building footprint and no more than one ADU resulting from new construction shall be allowed, including additions and garage or accessory structure conversions.

C.

Future Subdivision. Parcels upon which an ADU has been approved shall not be subdivided or otherwise segregated in ownership in a manner that would separate the ADU from the principal dwelling.

D.

Maximum Size. A detached ADU shall be no greater than 1,000 square feet, not including the garage or covered porches. The following areas shall be counted when calculating the size of an ADU:

1.

Habitable space as defined by the International Residential Code (IRC), and

2.

Kitchens, bathrooms, and utility/laundry rooms.

ADUs shall comply with the required site coverage, yard area requirements or building code setbacks as provided within the subject property's zone.

E.

Scale. A detached ADU or accessory structure containing an accessory dwelling unit shall not exceed the maximum height allowed for a detached accessory building per the underlying zoning district.

F.

Parking. At least one off-street parking space in addition to the minimum required off-street parking from the primary dwelling unit, shall be provided for each ADU.

G.

Utility Connections. Utility accounts for ADUs shall be maintained in the name of the property owner. ADUs may be served by the same water meter and sewer connection utilized for the primary residence if approved by the city. The city may require an applicant to provide documentation demonstrating capacity availability prior to allowing a joint connection. The city may require upgrades to a utility connection and the cost of such upgrades shall be borne by the applicant. Utility fees charged for the ADU shall be in accordance with Chapter 13.04. If water or sewer service is not provided by the city, then the rules of the water or sewer district shall apply as to whether an additional hook-up and connection fees are required. Any water or sewer service as referenced in this section is subject to water or sewer availability.

H.

Entrance Location. An attached ADU shall have a separate entrance to the outside from the entrance for the primary dwelling located in such a manner as not to appear as a second primary entrance to the structure.

I.

ADUs shall be subject to applicable design guidelines under Chapter 18.74.

(Ord. No. 909, § 2 (Exh. A), 6-18-2009; Ord. No. 948, § 53, 10-7-2010; Ord. No. 1120, § 3(Exh. A), 3-21-2019)

18.56.040   Review process.

A.

Application. An applicant for an ADU shall submit an application on a form as provided by the department, including all application fees as set forth in the city's fee schedule. At a minimum, an application for an ADU permit shall include plans for creating the ADU, evidence of current ownership and a certification of owner occupancy.

B.

Review by Director. ADU permit applications shall be processed as Type 2 permit pursuant to Chapter 18.08. Upon receipt of a complete application for an ADU, the director shall review and either approve, disapprove or approve with conditions the ADU application.

C.

Approval. Approval of the ADU shall be subject to the applicant recording a document in a form approved by the city with the King County Department of Records and Elections prior to approval which runs with the land and identifies the legal description and address of the property with a statement that the owner(s) will notify any prospective purchasers of any conditions imposed as part of the ADU approval with the requirements for continued use of the ADU as set forth in this chapter.

(Ord. No. 909, § 2 (Exh. A), 6-18-2009; Ord. No. 1120, § 3(Exh. A), 3-21-2019)

18.56.050   Recognition of existing accessory dwelling units.

ADUs that existed on or before the effective date of the ordinance codified in this chapter may be granted an ADU permit subject to the provisions of this section.

A.

Time Limit. An application for an ADU permit for a pre-existing unit must be filed with the city for review by the director within eighteen months of the effective date of the ordinance codified in this chapter.

B.

Construction Code Compliance. Any space used for or included in the ADU shall have been constructed pursuant to a building permit issued by the city, and in compliance with the building and other construction codes that were in effect when construction was completed.

C.

Development and Use Standards. Development and use of the pre-existing ADU shall comply with all provisions of this chapter.

(Ord. No. 909, § 2 (Exh. A), 6-18-2009; Ord. No. 1120, § 3(Exh. A), 3-21-2019)