Title 17C Land Use Standards
Chapter 17C.111 Residential Zones
Section 17C.111.240 Accessory Structures
Purpose.
This section regulates structures that are incidental to primary buildings to prevent them from becoming the predominant element of the site. The standards provide for necessary access around structures, help maintain privacy to adjoining lots and maintain open front setbacks. This section does not apply to accessory dwelling units (ADUs).
General Standards.
Accessory structures are allowed on a lot only in conjunction with a primary building and may not exist on a lot prior to the construction of the primary structure, except as allowed by subsection (B)(2) of this section.
An accessory structure that becomes the only structure on a lot as the result of a land division may remain on the lot if the owner has submitted a financial guarantee to the City for the cost of demolition and removal of the structure. The financial guarantee will be used by the City if the owner has not removed the accessory structure if, within one year of final plat approval or boundary line adjustment (BLA), a primary structure has not been built and received final inspection. The financial guarantee must be accepted by the City prior to approval of the final plat or boundary line adjustment.
An accessory structure shall not contain a kitchen or space for living, sleeping, eating, or cooking unless it is approved as an accessory dwelling unit under chapter 17C.300 SMC .
Setbacks.
Mechanical Structures.
Mechanical structures are items such as heat pumps, air conditioners, emergency generators, and water pumps.
Front Setback Standard.
Mechanical structures are not allowed in required front building setbacks.
Side and Rear Setback Standard.
Mechanical structures are allowed inside and rear building setbacks if the structure is no more than forty-eight inches high.
Vertical Structures.
Vertical structures are items such as flagpoles, trellises and other garden structures, radio antennas, satellite receiving dishes and lampposts. Fences are addressed in SMC 17C.111.230 . Sign standards are in chapter 17C.240 SMC , Signs.
Setback Standard.
Vertical structures are allowed in required side and rear building setbacks if they are no larger than four feet in width, depth or diameter and no taller than seven feet. If they are larger or taller, they are not allowed in required building setbacks. Trellises and other gate features are allowed in front yard if they are no larger than four feet in width, depth or diameter and no taller than seven feet and do not conflict with the clear view triangle provisions under SMC 17C.111.230 , Fences.
Uncovered Horizontal Structures.
Uncovered horizontal structures are items such as decks, stairways, entry bridges, wheelchair ramps, swimming pools, hot tubs, tennis courts, and boat docks that are not covered or enclosed.
Setback Standard.
Projection Allowed.
The following structures are allowed in required building setbacks, as follows:
Structures that are no more than two and one-half feet above the ground are allowed in side and rear building setbacks. Handrails required by the IBC/IRC are not included in the maximum height.
On lots that slope down from the street, vehicular or pedestrian entry bridges that are no more than two and one-half feet above the average sidewalk elevation are allowed in all building setbacks; and
Stairways and wheelchair ramps that lead to one entrance on the street-facing facade of a building are allowed in street setbacks.
Covered Accessory Structures.
Covered accessory structures are items such as greenhouses, storage buildings (not used to cover motor vehicles), sheds, covered decks, covered porches, gazebos, and covered recreational structures.
Setback Standard.
Front Setback.
Covered accessory structures are not allowed in the required front building setbacks.
Side Setback.
Covered detached accessory structures are not allowed in the required side building setback without a signed waiver from the neighboring property owner.
Covered attached accessory structures are not allowed in the required side building setback.
Detached Accessory Structures.
Detached accessory structures are garages, carports, and other structures utilized to cover motorized vehicles.
Setback Standard.
A detached accessory structure is not allowed in the front building setback. A detached accessory structure is not allowed in the required side building setback without a signed waiver from the neighboring property owner. A detached accessory structure that has an entrance facing a street side lot line shall be set back twenty (20) feet from the sidewalk. In the event there is no sidewalk, the setback shall be twenty-seven (27) feet from the back of curb.
Detached accessory structures may be built to the rear property line, unless parking in front of the structure is proposed, then the structure is required to be built a minimum of eighteen feet from the edge of the alley tract, easement, or right-or-way.
Attached Accessory Structures.
Accessory structures are garages, carports or other structures utilized to cover motorized vehicles that are connected by a common wall to the primary structure.
Setback Standard.
An attached accessory structure is not allowed in the front building setback. An attached accessory structure that has an entrance facing a street side lot line shall be set back twenty (20) feet from the sidewalk. In the event there is no sidewalk, the setback shall be twenty-seven (27) feet from the back of curb.
Attached accessory structures may be built to within five feet of the rear property line, unless parking in front of the structure is proposed, then the structure is required to be built a minimum of eighteen feet from the edge of the alley tract, easement, or right-or-way.
Building Coverage.
Except as provided in subsection (2) of this subsection (D), the combined building coverage of all detached accessory structures and covered accessory structures may not exceed fifteen percent of the total area of the site, and when combined with all other structures on-site shall not exceed the maximum building coverage of the base zone.
On lots smaller than five thousand five hundred square feet with an accessory dwelling unit, combined building coverage of all detached accessory structures and covered accessory structures may not exceed twenty percent of the total area of the site, and when combined with all other structures on-site shall not exceed the maximum building coverage of the base zone.
Building Height.
The building height of detached accessory structures and covered accessory structures is listed in Table 17C.111.205-2 . Accessory structures, which contain an ADU over a garage, are subject to the height limitations in chapter 17C.300 SMC , Accessory Dwelling Units.
Date Passed: Monday, November 20, 2023
Effective Date: Monday, January 1, 2024
ORD C36459 Section 16
