Chapter 15.30
ACCESSORY DWELLING UNITS
Sections:
15.30.020 Purpose and authority.
15.30.030 Standards and criteria.
15.30.060 Minimum yards for D-ADUs.
15.30.080 Permitting/recording.
15.30.090 Impact and connection fees.
15.30.100 Elimination/cancellation.
15.30.010 Definitions.
Where a defined term herein duplicates a term already defined in the zoning ordinance, the definition in this section shall prevail:
The definitions in this section apply throughout Wilbur Municipal Code, unless the context clearly requires otherwise.
“Accessory dwelling unit” means a dwelling unit located on the same lot as a single-family housing unit, duplex, triplex, townhome, or other housing unit.
“Attached accessory dwelling unit” means an accessory dwelling unit located within or attached to a single-family housing unit, duplex, triplex, townhome, or other housing unit.
“City” means any city, code city, and town located in a county planning under RCW 36.70A.040.
“County” means any county planning under RCW 36.70A.040.
“Detached accessory dwelling unit (D-ADU)” means an accessory dwelling unit that consists partly or entirely of a building that is separate and detached from a single-family housing unit, duplex, triplex, townhome, or other housing unit and is on the same property.
“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.
“Gross floor area” means the interior habitable area of a dwelling unit including basements and attics but not including a garage or accessory structure.
“Major transit stop” means:
1. A stop on a high-capacity transportation system funded or expanded under the provisions of Chapter 81.104 RCW;
2. Commuter rail stops;
3. Stops on rail or fixed guideway systems, including transitways;
4. Stops on bus rapid transit routes or routes that run on high occupancy vehicle lanes; or
5. Stops for a bus or other transit mode providing actual fixed route service at intervals of at least fifteen minutes for at least five hours during the peak hours of operation on weekdays.
“Owner” means any person who has at least fifty percent ownership in a property on which an accessory dwelling unit is located.
“Principal unit” means the single-family housing unit, duplex, triplex, townhome, or other housing unit located on the same lot as an accessory dwelling unit.
“Short-term rental” means a lodging use, which is not a hotel or motel or bed and breakfast, in which a dwelling unit, or portion thereof, is offered or provided to a guest by a short-term rental operator for a fee for fewer than thirty consecutive nights.
“Tiny home” means a small dwelling unit on a foundation with a minimum size of one hundred fifty square feet and no more than four hundred square feet of habitable floor area and shall comply with all applicable building design regulations. (Ord. 627 §1, 2025)
15.30.020 Purpose and authority.
A. It is the purpose of this legislation to implement policy provisions of the town’s comprehensive plan promoting increased housing options and innovation that will help meet the needs of the many sectors of the community. Further, the purpose is to preserve the small-town character of Wilbur and to give direction orderly growth and development, together with flexibility to respond to changing economic circumstances. It is intended for this legislation to help provide homeowners with flexibility in establishing separate living quarters within or adjacent to their homes, to increase the supply of accessible and affordable housing; to make more efficient use of public infrastructure, and to improve the economic and social well-being of the community.
B. The building inspector shall have the authority to approve accessory dwelling units (ADUs) which are consistent with the regulations and provisions herein. However, the town retains the right to review for approval applications for an ADU.
C. Enforcement. The town retains the right (with reasonable notice) to inspect an ADU for compliance with this chapter.
D. Any owner with an unpermitted ADU on the owner’s property shall be in violation of this subsection and subject to penalties, costs, and attorney fees. (Ord. 627 §2, 2025)
15.30.030 Standards and criteria.
A. An accessory dwelling unit (ADU) may be allowed in general use types where listed as a permitted use if the ADU complies with the requirements listed in this chapter.
B. An ADU shall comply with all zoning code provisions for the primary dwelling unit, including height, setbacks, floor area, accessory buildings and open space, except as provided in this section. This provision shall also apply to ancillary structures attached to a D-ADU such as garages, carports, garden sheds, and workshops.
C. Applicants may request minor modifications to the development and design standards for ADUs. A minor modification is a request by the applicant to meet or exceed a particular ADU standard through the use of a technique or alternative standard not otherwise listed under the applicable requirement. Minor modifications are not variances and are not required to meet all of the criteria typically associated with a variance application. The building inspector may grant a minor modification, subject to the town’s right to deny the request, if the following criteria are met:
1. The site is physically constrained due to, but not limited to, unusual shape, topography, easements, existing development on site, or critical areas; or
2. The granting of the modification will not result in a development that is less compatible with adjacent neighborhood land uses; and
3. The granting of the modification will not be materially detrimental to the public welfare or injurious to other land or improvements in the vicinity and district in which the property is situated; and
4. The granting of the modification is consistent with the purpose and intent of this section; and
5. All reasonable mitigation measures for the modification have been implemented or assured.
D. The owner of the ADU shall be liable for requesting and obtaining all necessary inspections and approvals for each ADU. The owner shall be liable for compliance with all federal, state, and local laws. (Ord. 627 §3, 2025)
15.30.040 Site requirements.
A. No more than two ADUs shall be permitted in conjunction with the primary dwelling unit on a single parcel of record. The parcel may not contain more than one primary dwelling unit. An ADU is exempt from density limitations and may be in any configuration of an attached or detached ADU.
B. The ADU shall have direct access to a public street via a pedestrian path, driveway, or alley.
C. No parking is required when improved public street parking is available on at least one side of the block face whereon the ADU is proposed, on-street parking is constructed, or the ADU is within one-half mile walking distance to a major transit route. (Ord. 627 §4, 2025)
15.30.050 ADU size.
A. Attached and Detached ADU. The gross square feet of an ADU shall not exceed one thousand square feet. The gross square feet of an ADU shall not be less than two hundred fifty square feet.
B. Attached ADUs (A-ADU). The maximum floor area of this section does not apply when the basement of a primary dwelling unit is converted to an A-ADU, and the primary dwelling unit has been on the site for at least five years.
C. Detached ADUs (D-ADU). The floor area for D-ADUs shall be calculated to include all attached ancillary space (garage, workshop, garden shed, etc.). Maximum allowed floor area limits are as follows:
1. A D-ADU with ancillary space may exceed one thousand square feet when approved by the town council by conditional use permit.
2. When an oversized detached accessory building approved by a conditional use permit has been on site for at least five years, conversion of said building to a D-ADU may occur without subsequent conditional use permit approval.
D. Building Height for D-ADUs. A D-ADU shall be no higher than twenty-four feet. (Ord. 627 §5, 2025)
15.30.060 Minimum yards for D-ADUs.
Front and side-flanking yards shall comply with the zoning code provisions for the primary dwelling unit except that when the vehicular entrance to an attached garage or carport faces a street, the entrance shall be set back a minimum of twenty-five feet from the front property line, and ten feet from a side flanking property line.
A five-foot side and rear yard setback shall be provided, measured from the property line to the foundation of the structure, except as follows:
A. When abutting an alley, there is no required side or rear yard setback from the alley.
B. A D-ADU may be located in a rear yard and in the rear twenty-two feet of an interior side yard, provided:
1. If a D-ADU is to be located less than five feet from any common property line, a joint agreement with the adjoining property owner(s) must be executed and recorded with the Lincoln County auditor’s office and thereafter filed with the town prior to issuance of a building permit; or
2. If site characteristics warrant such that, in the opinion of the director, impacts to abutting property would be negligible due to, but not limited to, one or more of the following:
a. The existing use and development pattern on abutting property.
b. Minimal disruption of solar access to outdoor recreation or garden space on abutting property compared to what may otherwise occur with the application of standard development regulations.
c. Site characteristics such as building a D-ADU downslope from abutting property.
d. Conversion of a detached accessory building that is at least five years old and has had no additions within the required side or rear yard within that time period.
e. A minimum six feet of separation is required between the primary dwelling unit and a D-ADU. (Ord. 627 §6, 2025)
15.30.070 Utilities.
A. Utilities Required. Each ADU shall be served by potable water, have an active sewer connection, and be served by electricity.
B. Water and Sewer. A primary dwelling unit and ADU(s) may have a shared water service to a water system, a shared sewer service to a sewer system and a shared storm service to a stormwater management system, in which case the primary dwelling unit will be responsible for all billing and maintenance of the services. When billing has a shared unit, there will be additional base unit fees. Separate and independent services from each building may be required to meet the city’s adopted plumbing code. In all cases, the water service shutoff must be accessible to occupants of all units. (Ord. 627 §7, 2025)
15.30.080 Permitting/recording.
An applicant seeking to build an accessory dwelling unit shall apply for an ADU permit with the building department. The application shall include an affidavit signed by the property owner agreeing to all the general requirements outlined in this section. An applicant seeking to build an ADU shall file a notice approved by town building inspector and deputy clerk. The notice shall run with the land. The applicant shall submit proof that the notice was filed before the department shall approve any permit for construction of the ADU. The required contents and form of the notice shall be set forth by the building inspector. If an accessory dwelling unit on a lot is going to be sold, a notice of intent to sell must be submitted to the town sixty days prior to sale. (Ord. 627 §8, 2025)
15.30.090 Impact and connection fees.
Impact fees for an ADU are limited to no more than fifty percent of those that would be assessed on the principal housing unit at the time the ADU application is approved. Connection fees shall be charged at the same rate that would be charged to the principal housing unit at time of the connection. (Ord. 627 §9, 2025)
15.30.100 Elimination/cancellation.
Elimination or cancellation of a registered ADU may be accomplished by the owner filing a certificate with the town of Wilbur for recording such change with the Lincoln County assessor’s office. Cancellation may also result from an enforcement action by the town. The ADU structure may be converted to another permitted or accessory use or permanently removed from the property. (Ord. 627 §10, 2025)