Pre-Approved ADU

An accessory dwelling unit (ADU) is a smaller, independent residential dwelling unit located on the same lot as a stand-alone (i.e., detached) single-family home. ADUs go by many different names throughout the U.S., including accessory apartments, secondary suites, and granny flats. (Source: American Planning Association)

KRCC worked with an architect to develop architectural plans for several different types of ADUs. These basic plans are pre-approved by jurisdictions in Kitsap County and can be used by residents and builders for faster permitting. The availability of these plans will support affordable housing efforts by making it easier and less expensive for community members to build ADUs on their property. 

The pre-approved ADU plans are available for use within Kitsap County, including within the city limits of Bainbridge Island, Bremerton, Port Orchard, and Poulsbo.

Anyone can use a pre-approved ADU plan in urban areas of Kitsap County and anywhere in Bremerton, Bainbridge Island, Port Orchard, or Poulsbo for free, as long as no modifications to the plan are made. The plans are not free to use in rural areas of unincorporated Kitsap County, which are defined as any area that is not in an Urban Growth Area (UGA) or Type I Limited Area of More Intensive Rural Development (LAMIRD). If your property is not eligible for a free plan, the plans are also available for purchase. If you live in unincorporated Kitsap County, you can determine whether you live in an area that is eligible for free plans by visiting the Kitsap County Pre-Approved ADU webpage.

The plan sets come with built-in flexibility that allow you to make choices about certain colors, styles, and materials. Other changes to the plans would require you to work with any architect and/or structural engineer to make changes to the plans and to go through a regular plan review and permitting process. You can make the following non-structural choices:

• Window Frame Colors

• Window Sill Heights*

• Window Operation*

• Roof Pitches/Styles

• Roof Materials

• Roof Color

• Roof Trim & Trim Color

• Roof Eaves/Overhang or None

• Siding Material(s)

• Siding Color

• Door Color

• Door Style

• Door Materials

• Lighting Fixtures

• All Interior Walls are Non-Load Bearing**

* If it is an egress window sill heights must be maintained and window operation must meet requirements of IRC2021 and Washington State Amendments.

**except the 800SF 2-story option

The following changes would require a structural engineer:

• Window Width Changes

• Window Location Changes

• Added Windows

• Taller Ceilings

• Dissimilar Plate Heights

• Foundation Changes (non slab on grade)

• Basement/Under House Storage

• Joisted First Floor w/ Crawl Space

• Altering Interior Walls of 800 2-Story Option

• Added Garages, Porches, Carports, etc.

• Roof Pitches Steeper than Existing Type Options

• Roof Styles Not Offered Per Type

• Adding or Subtracting from Floor Plate Size

• Adding a Level to Existing Design

Permit-ready building plans are available by request from Kitsap County, Bainbridge Island, Bremerton, Port Orchard, and Poulsbo. Please visit the websites of the jurisdiction where you wish to construct an ADU for local process requirements and information. 

Pre-approved plans remove the need for users to pay an architecture fee (unless they choose to modify the plans) and allow for faster permitting.

The plan sets were designed with principles of accessibility in mind. Several of the plan sets are one story, have 36 inch entry/bath doors, and have accessible hallways and bathrooms.