Washington Cities Streamline Pre-Approved DADU Programs

Lynnwood and Edmonds are creating catalogs of pre-approved detached accessory dwelling units to simplify the local permitting process.

Updated on Oct. 24, 2026 in Home Renovation

Washington Cities Streamline Pre-Approved DADU Programs

Live Poll

Should cities prioritize pre-approved designs to make building accessory units easier in your community?

Washington cities are launching pre-approved detached accessory dwelling unit (DADU) catalogs to address the state requirement of over 50,000 new housing units annually. Lynnwood and Edmonds recently introduced these programs to improve the efficiency and predictability of residential development.

Why it matters

State housing legislation has pushed cities to provide more resources for housing construction to meet significant population growth. By pre-approving designs, local governments aim to lower administrative hurdles for homeowners interested in building additional units.

Building a DADU can cost as much as $450,000, with design licensing fees for these projects currently costing roughly $1,000. Lynnwood is currently reviewing eight designs under 1,000 square feet after receiving 23 plan submissions.

The players

Lynnwood

This Washington city is currently reviewing eight DADU designs following a submission window held earlier this year.

Edmonds

This municipality launched its pre-approved DADU program in late July 2026 to help manage local housing demand.

Seattle

As a pioneer in local ADU policy, this city has maintained an established program for accessory units since 2020.

Everett

This city publicized three pre-approved design options in late June 2026 as part of its own effort to streamline housing permits.

The details

Cities are streamlining permitting by offering catalogs of pre-approved designs, allowing applicants to work directly with architects for site-specific plans. While Seattle has managed an ADU program since 2020, newer efforts in Lynnwood and Edmonds reflect an regional shift toward standardized residential construction.

Seattle launched its ADU program in 2020.
Lynnwood accepted DADU plan submissions from May 20 to July 2, 2026.
Everett publicized three pre-approved DADU designs in late June 2026.
Edmonds launched its DADU program in late July 2026.
Lynnwood plans to release its DADU catalog to the public in fall 2026.

Culture Shift

These programs represent a pivot toward sustainable living and dense urban planning, mirroring a broader societal shift to increase housing capacity through infill. The effort follows Washington state housing legislation that necessitates significant increases in residential construction.

Homeowners in Lynnwood and Edmonds may soon face a more predictable and potentially faster permitting process when adding a secondary unit to their property. These residents should budget for potential construction costs up to $450,000 while utilizing new city-approved design resources.

The takeaway

Pre-approved DADU catalogs offer a practical pathway for homeowners to increase property density while adhering to evolving state building codes. Prospective developers should monitor their local municipal websites for official catalog releases to take advantage of streamlined permitting.