18.165.030 Development standards.
Accessory dwellings shall conform to the development standards (e.g., height, setbacks, lot coverage, etc.) below:
A. Floor Area. Accessory dwelling units shall not exceed 800 square feet of floor area, or 75 percent of the primary dwelling’s floor area, whichever is smaller. However, accessory dwelling units that result from the conversion of a level or floor (e.g., basement, attic, or second story) of the primary dwelling may occupy the entire level or floor area, even if the floor area of the accessory dwelling would be more than 800 square feet.
B. Building Standards.
1. ADUs shall conform to the dimensional standards of the zone in which they are located, including setbacks and height. Lot coverage standards for ADUs may be reduced by 10 percent from those required by the zone in which they are located when a second ADU is proposed.
2. All housing and building codes and standards shall be applicable to ADUs, including, but not limited to, the building, plumbing, electrical, mechanical and fire codes.
C. Other Development Standards.
1. Conversion of an existing legal, nonconforming structure to an accessory dwelling is allowed; provided, that the conversion does not increase the nonconformity.
2. Off-street parking is not required for a single accessory dwelling provided the driveway to the existing single-family dwelling is improved in accordance with TMC 18.110.130 and accommodates the required parking in accordance with TMC 18.110.060. A secondary accessory dwelling unit shall include an additional single parking space.
3. Attached ADUs shall have a separate entrance to the accessory dwelling unit, but it shall not be located on the front of the existing building.
4. Detached ADUs shall share the same hard-surfaced driveway and driveway access as the single-family dwelling to which such ADU is accessory, and shall have direct access to the street upon which the single-family dwelling fronts, or take access from an alley. No new curb cuts shall be permitted for the ADU, except on corner lots where a new curb cut will be allowed on the street frontage having no existing curb cut. New curb cuts shall be allowed only on local streets.
5. All ADUs shall have a separate street address, visible from the abutting street frontage and clearly identifying the site location of the ADU. [Ord. 943 § 1 (Exh. A), 2018; Ord. 817 § 8-3L.530, 2006.]