Columbia County Unincorporated
City Zoning Code
City Zoning Code
CHAPTER 18
122 ACCESSORY DWELLING UNITS
§ 18.122.010 Purpose.
In accordance with RCW 36.70A.696, the purpose of these code provisions for accessory dwelling units (ADUs) is to (A) provide homeowners with flexibility in establishing separate living quarters within or adjacent to their homes for the purpose of caring for seniors, providing housing for family members, or obtaining rental income; (B) increase the range of housing choices and the supply of accessible and affordable housing units within the community; and (C) ensure that the development of accessory dwelling units does not cause unanticipated impacts on the character or stability of single-family neighborhoods.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)
§ 18.122.020 Definitions.
A. "Accessory dwelling unit (ADU)"
means a subordinate dwelling unit located on the same lot as a single-family housing unit, duplex, triplex, townhome, or other housing unit.
B. "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.
C. "Detached accessory dwelling unit"
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.
D. "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.
E. "Owner"
means any person who has 50 percent ownership in a property on which an accessory dwelling unit is located.
F. "Short-term rental"
means a lodging use, that 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 30 consecutive nights.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)
§ 18.122.030 Designation.
One accessory dwelling unit (ADU) shall be permitted in any zone where single-family dwellings are listed as a permitted use only on parcels which meet the following conditions:
A.
Is a legal lot of record sufficient to support water and septic.
B.
Contains an existing single-family dwelling, which is conforming in use.
C.
Contains no other accessory dwelling.
D.
The new ADU conforms to all current bulk and dimension standards of the zone.
E.
The ADU may be constructed within the existing structure, attached as a new addition or partial addition or detached either built on site or moved to the site, including state-certified manufactured or modular homes set on a permanent foundation as real property.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)
§ 18.122.040 Procedure.
Each accessory dwelling unit shall require an administrative permit as follows:
A.
The permit for an ADU shall be considered a nondiscretionary permit to be approved administratively by the planning director.
B.
The required fee as established by the BOCC shall be submitted with the application.
C.
The application shall be made in accordance with submittal requirements on file with the planning department.
D.
Prior to submitting an application the applicant shall meet with the planning department to determine compliance of the property with current zoning codes.
E.
An applicant seeking to build an accessory dwelling unit shall file a Columbia County accessory dwelling unit affidavit that identifies the dwelling unit as accessory and stipulates regulations. The applicant shall submit proof that the notice was filed before a permit for construction is approved. The notice shall run with the land.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)
§ 18.122.050 Standards.
A.
New construction for an ADU shall comply with all the development standards for a single-family dwelling including, but not limited to, setbacks, height limits, and lot coverage and shall not increase any nonconforming aspect of any existing structure unless otherwise addressed by this chapter.
B.
The following standards shall also apply:
1.
The accessory dwelling unit, excluding any garage area and other nonhabitable spaces, shall not exceed 1,100 square feet, or 50 percent of the total square footage of the primary residence, excluding any garage area and other nonhabitable spaces, whichever is less.
2.
Both the ADU and the primary unit shall comply with all applicable building codes.
3.
If the ADU is attached to the primary building, the main exterior entrances may not be on the same side of the building.
4.
The ADU should be designed to be compatible with the primary dwelling unit, taking into consideration materials, colors and building forms.
5.
One off-street parking space shall be provided for the ADU in addition to those required for the primary dwelling.
6.
There shall be no more than three bedrooms in an ADU.
7.
The ADU shall be no more than 100 feet away from the primary residence.
a.
The planning director shall have authority to permit an additional 50-foot distance from the primary residence only if topography and/or the placement of existing structures requires.
8.
Travel trailers and recreational vehicles shall not be permitted as accessory dwelling units.
10.
Any additions to the ADU shall meet the requirements of this chapter.
C.
An accessory dwelling unit which conforms to the standards in this chapter shall not be considered to exceed the allowable density for the lot upon which it is located and shall be considered a residential use which is consistent with the comprehensive plan and zoning designation for the lot.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)
§ 18.122.060 Additional requirements.
Accessory dwelling units shall be subject to the following requirements:
A.
Sale or ownership of such unit separate from the primary residential unit is prohibited.
B.
If the ADU is being offered or used as a short-term rental, the occupant of either the ADU or the primary unit shall be the owner of the entire property.
C.
Prior to issuance of a permit for ADU evidence shall be provided that there is adequate potable water and sanitary sewer capacity for an additional dwelling unit on the lot.
D.
Prohibited occupancy or sale, in addition to authorizing all other remedies available to the county, shall constitute a zoning violation and a nuisance subject to abatement.
(Ord. 2013-01 § 1 (Exh. A); Ord. 2019-06 § 2 (Exh. C); Ord. 2021-05)