Title 17C Land Use Standards
Chapter 17C.300 Accessory Dwelling Units
Section 17C.300.110 Criteria
- Maximum Size.
- Internal ADU.
Before the establishment of an internal ADU the floor area of the principal structure, excluding an attached garage, must be not less than eight hundred square feet.
- The internal ADU shall contain no more than two bedrooms and the floor area of the internal ADU must be not more than eight hundred square feet, excluding any related garage are
- The conversion of an existing interior basement or attic space of a principal structure into an ADU may exceed the maximum floor area for an internal ADU specified in subsection (1)(a) of this subsection.
- Detached ADU.
- The maximum detached ADU size is subject to building coverage per SMC 17C.300.130(B)(3) and floor area ratio per subsection (3) of this subsection (A); and
- A detached ADU shall not exceed seventy-five percent of the floor area of the principal structure, or nine hundred seventy-five square feet of floor area, whichever is greater.
- The maximum detached ADU size is subject to the maximum building footprint standards for ADUs in Table 17C.111.205-2.
- Occupancy for Short-Term Rentals.
Where a lot with an ADU also has a Short-Term Rental under chapter 17C.316 SMC, one of the dwelling units on the lot shall be occupied by one or more owners of the property as the owner’s permanent and principal residence. The owner-occupant must occupy the owner-occupied dwelling unit for more than six months of each calendar year. The owner-occupant may not receive rent for the owner-occupied dwelling unit. If a complaint that an owner has violated these requirements is filed, the owner shall:
- submit evidence to the director showing good cause, such as a job dislocation, sabbatical leave, education or illness, for waiver of this requirement for up to one year absence from the property. Upon such showing the director may waive the requirement;
- re-occupy the structure; or
- remove the accessory dwelling unit.
Date Passed: Monday, November 20, 2023
Effective Date: Monday, January 1, 2024
ORD C36459 Section 26
Section 17C.300.110 Criteria
- Maximum Size.
- Internal ADU.
Before the establishment of an internal ADU the floor area of the principal structure, excluding an attached garage, must be not less than eight hundred square feet.
- The internal ADU shall contain no more than two bedrooms and the floor area of the internal ADU must be not more than eight hundred square feet, excluding any related garage are
- The conversion of an existing interior basement or attic space of a principal structure into an ADU may exceed the maximum floor area for an internal ADU specified in subsection (1)(a) of this subsection.
- Detached ADU.
- The maximum detached ADU size is subject to building coverage per SMC 17C.300.130(B)(3) and floor area ratio per subsection (3) of this subsection (A); and
- A detached ADU shall not exceed seventy-five percent of the floor area of the principal structure, or nine hundred seventy-five square feet of floor area, whichever is greater.
- The maximum detached ADU size is subject to the maximum building footprint standards for ADUs in Table 17C.111.205-2.
- Occupancy for Short-Term Rentals.
Where a lot with an ADU also has a Short-Term Rental under chapter 17C.316 SMC, one of the dwelling units on the lot shall be occupied by one or more owners of the property as the owner’s permanent and principal residence. The owner-occupant must occupy the owner-occupied dwelling unit for more than six months of each calendar year. The owner-occupant may not receive rent for the owner-occupied dwelling unit. If a complaint that an owner has violated these requirements is filed, the owner shall:
- submit evidence to the director showing good cause, such as a job dislocation, sabbatical leave, education or illness, for waiver of this requirement for up to one year absence from the property. Upon such showing the director may waive the requirement;
- re-occupy the structure; or
- remove the accessory dwelling unit.
Date Passed: Monday, November 20, 2023
Effective Date: Monday, January 1, 2024
ORD C36459 Section 26
