Pullman City Zoning Code
17.100 Accessory
Dwelling Units
All accessory dwelling units (ADUs) must comply with the following:
(1) Creation. An ADU may be created on a lot with another dwelling unit, through one of the following:
17.100.010 Purpose.
This Chapter is to:
(1) Encourage development of a viable economic base that enhances the image of the City;
(2) Promote affordable housing, efficient use of land and energy, and a variety of housing types in a variety of locations;
(3) Encourage creativity in design; and
(4) Permit within residential neighborhoods the development of accessory dwelling units built to standards designed to include amenities usually associated with conventional single-family detached housing, and to ensure their compatibility with the surrounding neighborhood. (Ord. 25-08 §1 (Att. A), 2025).
17.100.020 Development Standards.
All accessory dwelling units (ADUs) must comply with the following:
(1) Creation. An ADU may be created on a lot with another dwelling unit, through one of the following:
(a) Converting an existing living area, attic, basement, or garage;
(b) Adding floor area;
(c) Constructing a detached ADU on a site with an existing residential use; or
(d) Constructing a new residential use with an internal or detached ADU.
(2) Number of ADUs. One (1) ADU is allowed per lot, regardless of zoning density, provided all other requirements are met. Additional ADUs are allowed on the same lot as long as the underlying zoning district density as provided for in PCC 17.75.070(3) is still met.
(3) Conversion of Existing Detached Structure.
(a) If an ADU is proposed in an existing detached accessory structure that meets the standard of the underlying zoning district, alterations that would cause the structure to be out of conformance with the standards of the underlying zoning district are not allowed.
(b) If an ADU is proposed by converting an existing detached accessory structure or a portion of the accessory structure, any proposed addition to the existing structure must meet the standards of the underlying zoning district.
(4) Parking. Parking must conform with the primary structure.
(5) Utilities. The ADU must be connected to City utilities and will be jointly metered with the principal residence. Separate connections may be allowed by the Director of Public Works.
(6) Addressing. The ADU will have the same address as the principal residence but each residence will be identified as a unit.
(a) Example 1. Principal residence address 123 E Main Street, Unit A and ADU address 123 E Main Street, Unit B.
(b) Example 2. Principal residence address 123 E Main Street, Unit 1 and ADU address 123 E Main Street, Unit 2. (Ord. 25-08 §1 (Att. A), 2025).
17.100.030 Design Standards.
(1) Size. ADUs will be a minimum of 200 square feet and a maximum of 900 square feet.
(2) Setbacks.
(a) An existing accessory structure with legal non-conforming setbacks may be converted. However, the accessory structure cannot be enlarged, as that would create more non-conformities than already exist.
(b) All new ADUs must follow the minimum required yards provided in PCC 17.75.070(7).
(c) New detached ADUs must be a minimum of 10 feet from other structures on the property.
(3) Height.
(a) Attached ADUs. Attached ADUs will have the same height limitation as the principal residence as provided in PCC 17.75.070(6).
(b) Detached ADUs. The maximum height allowed for detached ADUs is provided in PCC 17.75.070(6).
(4) Facilities. The ADU must include at least a kitchen, bathroom, and sleeping facilities.
(5) Building Coverage. An increase of 10% lot coverage from the underlying zoning district will be allowed for creation of ADUs. (Ord. 25-08 §1 (Att. A), 2025).
17.100.040 Procedure for Approval and Effect of Approval.
(1) ADUs built on site will be reviewed and permitted in the same manner as traditional site-built homes, and must comply with the most current state and local codes.
(2) Factory assembled, premanufactured, or modular ADUs must comply with the Washington State Department of Labor and Industries Factory Assembled Structures Division requirements and standards. Installation of factory assembled, premanufactured, or modular ADU will be permitted and inspected by the City.
(3) An ADU cannot be subdivided or under separate ownership from the principal residence unless the resulting lots meet all the required minimum development standards of this Title.
(4) The property owner will file a restrictive covenant with the Whitman County Auditor’s Office for the subject property prior to the issuance of a Certificate of Occupancy for the ADU. The recorded information will:
(a) Identify the property by address and legal description;
(b) State that the ADU will not be subdivided or otherwise segregated in ownership from the principal residence unless the resulting lot meets all required minimum development standards for the zoning district; and
(c) Provide, with proper notice, for the removal of the ADU within two (2) years, if any of the requirements of the City of Pullman Zoning Code are violated. (Ord. 25-08 §1 (Att. A), 2025).
17.100.050 Additional Regulations.
(1) Chapter 17.25 PCC, Assurances.
(2) Chapter 17.35 PCC, Exceptions and Special Provisions Pertaining to Uses, Development Regulations, and Performance Standards.
(3) Chapter 17.40 PCC, Off-street Parking and Loading.
(4) Chapter 17.45 PCC, Landscaping and Screening.
(5) Chapter 17.50 PCC, Sign Regulations.
(6) Chapter 17.75 PCC, Residential Districts.
(7) Chapter 17.105 PCC, Manufactured Homes, Tiny Homes, Recreational Vehicles, and Trailers.
(8) Chapter 17.135 PCC, Site Plan Review. (Ord. 25-08 §1 (Att. A), 2025).