12.14.135 Accessory dwelling units.
A. Accessory dwelling units are an accessory use to a primary dwelling unit and may be an additional room, set of rooms, or a separate structure all of which are a secondary use to the primary use of a property as a single-family dwelling.
B. Accessory dwelling units are permitted subject to the following requirements:
1. Either the primary dwelling unit or the accessory dwelling unit shall be occupied by an owner of the property or by an immediate family member of the property owner. The owner or immediate family member of the owner must occupy one of the dwelling units on the property for more than six months of each calendar year.
2. The total number of occupants in both the primary residence and accessory dwelling unit combined may not exceed the maximum number of occupants allowed in a household per BMC 12.06.140(B)(9).
3. Wherever practicable, a house shall have only one entrance on the front, with additional entrances permitted on the side and rear. On corner lots, it is permissible to locate the entry door to the accessory dwelling unit on a street side of the structure other than the street side with the entry door for the principal dwelling unit. The entrance to an attached accessory dwelling unit may be on the front of the house only if (a) it is located in such a manner as to be clearly secondary to the main entrance to the principal dwelling unit; (b) it is screened from the street; and (c) it shall not detract from or alter the single-family character of the principal dwelling unit.
4. At least one additional paved off-street parking stall shall be provided in addition to any parking required for the primary dwelling unit; such parking shall consist of a driveway, carport, garage, or a combination thereof, located on the lot they are intended to serve.
5. The size of an accessory dwelling unit shall be limited as follows:
a. The floor area devoted to an accessory dwelling unit shall comprise no more than two-thirds of the primary dwelling unit, or 40 percent of the total floor area of the primary dwelling unit and the accessory dwelling unit combined, excluding any garage area; or 800 square feet, whichever is less. 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.
b. Detached accessory dwelling units are exempt from the provisions of BMC 12.14.130 that limit the size of accessory buildings to five percent of the lot area.
6. Detached accessory dwelling units shall have a height no greater than 25 feet or no greater than 28 feet for units over an existing accessory structure.
7. A single-family lot shall contain no more than one accessory dwelling unit.
8. The property owner shall apply for an accessory dwelling unit permit and pay any applicable application fee as set by the city. The application shall include an affidavit signed by the property owner agreeing to all the general requirements outlined in this section.
9. Approval of the accessory dwelling unit shall be subject to the applicant recording a document with King County or Snohomish County, which document (a) runs with the land and identifies the address of the property, (b) states that the owner(s) resides in either the principal dwelling unit or the accessory dwelling unit, (c) includes a statement that the owner(s) will notify any prospective purchasers of the limitations of this section, and (d) provides for the removal of the accessory dwelling unit if any of the requirements of this chapter are violated.
10. For existing accessory dwelling units that were created without an approved application, the property owner must still apply to the city for approval. If an accessory dwelling unit was created without a building permit that was finalized, the city shall require a building inspection to determine whether the structure is sound, will not pose a hazard to people or property, and meets the requirements of this section and BMC Title 20. The accessory dwelling unit application fee will cover the building inspection of the accessory dwelling unit.
11. Two-story, detached accessory dwelling units shall be designed to protect the privacy of adjacent residential uses by employing all of the following techniques, as applicable:
a. For any walls that are less than 10 feet from the property line, second-level openings facing adjacent residential uses where sill heights are less than six feet above the second-level floor must use nontransparent windows or glass block.
b. Second-level decks less than 10 feet from the property line must be oriented away from adjacent residential uses or provide a minimum six-foot-tall, sight-obscuring screen facing the adjacent residential use. Entry stoops and landings are exempt from this requirement.
c. Where any walls that are 10 feet or more from the property line have second-level openings or decks facing adjacent residential properties, vegetative screening that will be sight-obscuring at maturity must already exist or be planted to screen the opening or deck from the adjacent residential use. (Ord. 2277 § 1, 2019; Ord. 2258 § 5, 2018).