Pre-Approved ADU Plans in Washington
Washington ADU Programs · Homeowner Guide
Pre-Approved ADU Plans in Washington: What They Include, What They Don't
A city-by-city guide to Washington's pre-approved ADU programs, and the site-specific permit work homeowners still need before construction can begin.
Building an accessory dwelling unit in Washington usually starts with design. Traditionally, that means hiring an architect or designer to create a complete set of building plans, coordinating structural engineering, and submitting those drawings to the city for review from scratch.
Pre-approved ADU programs remove a large part of that step. Instead of designing an ADU from the ground up, homeowners can choose a building design the city has already reviewed. Depending on the jurisdiction, that can include architectural drawings, structural engineering, and energy code documentation.
There is an important distinction worth understanding before you pick a plan: pre-approved does not automatically mean permit-ready for your property. The city already knows the building itself complies with code. It still has to confirm that building can be constructed on your specific lot, and that review can cover zoning, setbacks, lot coverage, utilities, drainage, and other site conditions.
In other words, the pre-approved plan solves the building design. The remaining permit work is about making that building work on your property. Here is how some of Washington's major pre-approved and permit-ready plan programs work, and what still has to happen after you pick one. Programs still in development are noted at the end.
Kitsap County: Bainbridge Island, Bremerton, Port Orchard, Poulsbo
These four cities share one regional program, run through the Kitsap Regional Coordinating Council. Six designs are available, ranging from a 480 square foot studio up to a 1,000 square foot option, all created by the same local architecture firm.
How it works: You review the shared catalog, then request the full stamped plan set through your specific city's planning department, since each city handles the request and submission a little differently even though the designs themselves are shared.
The advantage: No architect fee, and no waiting on a first time design review, since that part is already done.
Still needed for your permit: The ADU still has to fit the setbacks, lot coverage, and utility conditions on your specific parcel, and the jurisdiction may ask for additional site documentation before issuing the permit. Evergreen can confirm whether a given design actually works on your lot and prepare that piece.
One thing worth knowing before you get attached to a floor plan: the plans are free inside city limits and inside an urban growth area. In rural unincorporated Kitsap County, the same designs are available, but for purchase rather than free.
Seattle: ADUniverse
Seattle's program, ADUniverse, currently offers ten pre-approved detached ADU designs, each created by a different local designer or architect who retains ownership of the plan.
How it works: You browse the gallery, choose a design, and license it directly from that designer, which can cost up to $1,000. From there, the site-specific package goes to the Seattle Department of Construction and Inspections for review.
The advantage: The city estimates a pre-approved design shortens the permitting timeline by two to six weeks and saves around $1,500 in permit fees compared to a custom design.
Still needed for your permit: Choosing a design does not remove the site-specific application. The city still needs to see where the ADU sits on the lot and confirm zoning, setbacks, drainage, grading, utilities, and fire access, none of which can be resolved by the building design alone.
Seattle is currently updating this catalog under what it is calling ADUniverse 2.0, expanding beyond detached ADUs into a wider range of middle housing types. If a client's project could benefit from a type outside the current ten designs, it is worth checking whether an updated option is close to release.
Tacoma
Tacoma offers four base DADU models, each with different roof and siding options, all designed to fit the city's Home in Tacoma zoning standards.
How it works: Plans are already compliant with building, residential and energy code, so the main step left is an extensive pre-application process, including a site visit with city staff to flag anything specific to the lot before submission.
The advantage: The city provides the plans, the site evaluation, and support information at no cost, and because the code compliance review is already done, permitting and plan check move faster once the application is in.
Still needed for your permit: The city's site visit exists precisely because a code-compliant building still has to be placed correctly on an individual lot. Development standards and site-specific documentation still apply after the model is chosen.
Olympia, Lacey, Tumwater
These three cities partnered to commission a shared set of pre-approved ADU plans, offered free to property owners in each participating city.
How it works: Choose from the shared catalog, which includes six sizes from a 480 square foot studio up to a 1,000 square foot rambler, then request the plan set through your city's planning department. Exterior details like roof style, siding, color, windows and doors can be customized without triggering a new design review.
The advantage: Free plans, faster review, and enough exterior flexibility that the ADU can still fit the character of the existing home.
Still needed for your permit: Even with a reviewed building design, the city still needs to understand what happens around it: where it sits, how roof runoff is handled, how water and sewer connect, whether setbacks work, and whether the parcel touches an environmentally sensitive area. A site plan addressing those questions is still part of the application.
Send us your project address and we'll tell you which jurisdiction's catalog applies, and what site-specific work it actually takes to get permitted.
Port Angeles: Permit-Ready Plans
Port Angeles has one of the more comprehensive permit-ready plan programs in Washington, offering free plans not just for ADUs, but also for duplexes, small lot homes, and townhome configurations, including both building and engineering documents.
How it works: Download a plan and its supporting documentation directly from the city's website at no cost, then submit it with a standard building permit application.
The advantage: The city estimates this removes what would normally be a one to four month wait for custom architect and engineering drawings, and it goes further than most programs since much of the engineering work is already done.
Still needed for your permit: The project still has to be submitted for review and approved for the actual property where it will be built. That means confirming zoning, lot fit, and any site-specific conditions before the permit is issued.
Wenatchee and East Wenatchee
Wenatchee and East Wenatchee developed a joint program with fifteen pre-approved ADU designs, ranging from 400 to 1,200 square feet, the largest catalog on this list.
How it works: Browse the designs by size on either city's website, then submit a building permit application referencing the plan you have selected.
The advantage: Free plans, a shorter review time, and a reduced permit fee compared to a custom design.
Still needed for your permit: Utility plans are separate from the pre-approved building plans and still need to be addressed as part of the application. Homeowners may also need a site plan, energy documentation, and water and sewer approvals. That stays true even though the building design itself is free.
Renton: Permit Ready ADU Program (PRADU)
Renton offers eight pre-approved ADU designs ranging from about 415 to 1,000 square feet, and goes further than most cities on fees.
How it works: Select a model, then work one-on-one with city staff to fit the site-specific plan to your lot.
The advantage: The plans are free, and the city waives the permit review fee entirely for PRADU applications, along with transportation, fire, parks and school impact fees for ADUs built within the Renton School District.
Still needed for your permit: An approved design does not automatically mean it can be built anywhere on a given property. Lot configuration, zoning, placement, drainage, and utility conditions still matter, and Renton's own site-specific process is what determines whether they line up.
Kirkland
Kirkland operates a pre-approved detached ADU program with plans submitted by architects, designers, and builders and displayed in an online gallery, similar in structure to Seattle's ADUniverse.
How it works: Browse the gallery, select a design, and pay the designer's royalty, set at up to $1,000, to license the plan for use on your property.
The advantage: The city has already reviewed the underlying building design for Washington energy code, structural, and program criteria compliance, which can make permitting faster and more predictable.
Still needed for your permit: The homeowner still has to confirm the selected design fits the lot and complete the site-specific portion of the application, which can include a site plan, drainage or stormwater documentation, utility information, and other supporting documents depending on the property.
Leavenworth
Leavenworth partnered with Syndicate Smith LLC, a local architecture firm, to develop a set of pre-approved ADU designs for the city, each under 900 square feet.
How it works: Homeowners select a design and license it through Syndicate Smith, who can also help prepare a site plan and provide construction administration services before the permit application goes in.
The advantage: The building design itself, including structural and energy code compliance, is already resolved, which can meaningfully shorten the design phase of the project.
Still needed for your permit: Setbacks, lot coverage, and utility conditions still determine whether a given design fits a specific lot, and a site plan remains part of what the city requires. Larger ADUs up to 1,200 square feet are allowed in Leavenworth, but do not currently have pre-approved plans available.
Bellevue: Program in Development
Bellevue is building a pre-approved plans program for DADUs and cottage housing, expected to offer up to ten city-reviewed plans available for purchase. As of now, it is still in development, with the city targeting a launch aligned with the next state building code update. Homeowners considering an ADU in Bellevue should check the current program status before committing to a custom design, especially if the project is still in the early planning stages.
Lynnwood: Program in Development
Lynnwood is developing its own pre-approved DADU plan program. The city's submission window for designers closed in July 2026, with selected applicants moving into a second round of review shortly after. The program is not yet available to homeowners, but it is worth checking on if you are planning a project in Lynnwood on a longer timeline, since additional pre-approved options may become available.
What You Still Need to Get Permitted
A pre-approved plan solves one of the most expensive parts of an ADU project: designing the building itself. It does not solve how that building sits on your land. Depending on your jurisdiction and property, the remaining permit package can include:
- A site or plot plan showing property lines, setbacks, existing structures, and the proposed ADU
- Utility plans or documentation for water, sewer, power, and other services
- Stormwater or drainage information
- Site-specific foundation design or structural modifications where required
- Grading information
- Energy code documentation
- Tree protection information
- Critical area, flood, slope, or geotechnical documentation when applicable
- Fire access or hydrant information
- Separate utility or right-of-way permits
- Jurisdiction-specific applications, forms, and supporting documents
Not every property needs every item on this list. That is exactly why the first step is figuring out what your jurisdiction, and your specific lot, actually require.
Where Evergreen Permits Fits In
Across every one of these programs, the floor plan is usually the easy part. The friction shows up around it: confirming which jurisdiction's program actually applies to your address, checking that your lot and zoning qualify before you get attached to a specific design, preparing the site plan and utility documentation that every city still requires even with a pre-approved design, and staying on top of a submission through a department that does not always respond quickly.
That is the layer Evergreen Permits handles. We check site feasibility against the specific pre-approved catalog available where you live, help you choose a design that will actually work on your lot, identify the remaining permit requirements for your property, assemble and submit the full application the way your city wants it, and stay on the permit until it is issued.
Not Sure Whether a Pre-Approved Plan Works for Your Property?
Send us your project address. We'll identify which jurisdiction governs the property, confirm whether a pre-approved program is available, and tell you what site-specific drawings and documents are still needed to get your project permitted.
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