Gig Harbor City Zoning Code
17.69 Accessory
Dwelling Units
17.69.010 Intent.
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 their children 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 neighborhoods. (Ord. 1540 § 2, 2025).
17.69.020 Applicability.
The regulations established in this chapter apply to all accessory dwelling units proposed or located within or detached from legally established dwelling units. (Ord. 1540 § 2, 2025).
17.69.030 General regulations.
Accessory dwelling units are permitted outright in all residential zones that permit single-family homes and may be developed with new or existing principal dwelling unit. The development standards of the underlying zone and the following siting and performance standards shall apply to all accessory dwelling units as defined by GHMC 17.04.015.
A. Development Standards for Accessory Dwelling Units. An ADU shall comply with the following standards:
1. Configuration. An ADU may be located either within, attached to, or detached from the principal dwelling unit. Primary dwelling units include single-family housing unit, duplex, triplex, townhome, or other housing unit.
2. Density. Up to two ADUs may be created in conjunction with each principal dwelling unit. ADUs are exempt from the density requirements of the underlying zone.
3. Minimum Lot Size. An ADU may be established on any legally established parcel meeting minimum lot size per building site of the zoning district in which the principal dwelling unit is located.
4. Maximum Unit Size. The gross floor area, calculated from finished wall to finished wall. ADU shall not exceed 1,200 square feet, excluding any related garage area.
5. Minimum Unit Size. The gross floor area of an ADU shall not be less than the requirements of the Washington State Building Code.
6. Setbacks and Lot Coverage. Additions to existing structures, or the construction of new detached structures, associated with the establishment of an ADU shall not exceed the allowable lot coverage or encroach into required setbacks as prescribed in the underlying zone. The applicable setbacks shall be the same as those prescribed for the primary structure, not those prescribed for accessory structures.
7. In addition to any off-street spaces required for the primary residence, and except when the property is located within one-half mile of a major transit stop, off-street parking shall be provided for accessory dwelling units pursuant to Chapter 17.72 GHMC.
8. Design and Appearance. ADUs that are attached to or detached from existing structures shall conform to the applicable design standards contained in Chapter 17.99 GHMC.
9. Construction Standards. The design and construction of the ADU shall conform to all applicable standards in the building, plumbing, electrical, mechanical, fire, health and any other applicable codes. (Ord. 1540 § 2, 2025).