Washington Cities Launch Pre-Approved DADU Design Plans
Homeowners in Lynnwood and Edmonds can soon use pre-approved designs to streamline their accessory dwelling unit projects.
Updated on Oct. 24, 2026 in Home Renovation
Live Poll
Should cities prioritize pre-approved designs to make building accessory units easier in your community?
Lynnwood and Edmonds are rolling out new pre-approved design catalogs for detached accessory dwelling units (DADUs) to simplify residential construction. These programs aim to reduce permitting hurdles for homeowners interested in adding small-scale secondary housing.
Why it matters
Streamlined permitting addresses the state's urgent need for 50,000 new housing units annually by making the design and approval process more predictable. This shifts the focus toward efficiency to help residents navigate the high costs associated with new construction.
Lynnwood is currently reviewing 8 DADU designs under 1,000 square feet after receiving 23 submissions. While total building costs can reach $450,000, design licensing fees for these units are roughly $1,000.
The players
Lynnwood
A city government in Snohomish County working to streamline residential permitting through a new DADU design catalog.
Edmonds
A municipal government that recently launched a pre-approved program to encourage the construction of secondary dwelling units.
Seattle
A metropolitan government with an established ADU program that serves as a regional model for housing density initiatives.
Everett
A municipal authority that has already publicized pre-approved designs to assist local property owners.
The details
Cities are curating catalogs of pre-approved designs to expedite the city planning and zoning review process. Once a catalog is live, homeowners can select a plan and contact the architect directly to prepare the specific site plans and building permits. This approach is intended to provide greater predictability in the time and expense required to secure construction approval.
Timeline
2020: Seattle launched its initial accessory dwelling unit program.
May 20 to July 2, 2026: Lynnwood accepted initial DADU plan submissions.
Late June 2026: Everett publicized three pre-approved DADU designs.
Late July 2026: Edmonds officially launched its pre-approved DADU program.
Fall 2026: Lynnwood anticipates releasing its finalized DADU catalog.
The Home Front
These municipal programs follow a pattern set by Washington state housing legislation to address a deficit of 50,000 housing units per year. The efforts align with a broader shift in local zoning toward easing the development of secondary housing on residential lots.
If you are planning to add a detached unit, check your city's official planning website for upcoming catalog releases to potentially save on design and permitting time. Always consult with a licensed architect or builder to assess site-specific feasibility and total project costs.
The takeaway
Pre-approved design catalogs are designed to save homeowners time and administrative costs by streamlining the early stages of the permitting process. Keep an eye on your local city council's planning page for these catalogs to reduce the complexity of your upcoming renovation projects.
What happens next
Lynnwood expects to release its public catalog of pre-approved DADU designs in the fall of 2026, and new state building codes are scheduled to take effect in 2027.
Further reading
Learn more about the latest building trends in Washington Home Renovation.
Source note: This article includes information reported by My Edmonds News.
Live Poll
Should cities prioritize pre-approved designs to make building accessory units easier in your community?
