Seattle's pre-approved DADU plans: real timeline savings
What the SDCI pre-approved DADU plans program actually shaves off the schedule — and the trade-offs nobody discusses up front.
What the program is
Seattle DCI maintains a catalog of pre-approved DADU plan sets contributed by local architects. Building on a pre-approved plan moves your project to an expedited review track and waives most of the architectural plan-check scope, because the prototype has already been reviewed for code compliance.
The catalog spans roughly 30 plan sets across 1- and 2-story configurations from about 400 to 1,000 sqft.
Actual timeline delta
SDCI's published median for a standard DADU permit in 2024–2025 was 22–28 weeks from intake to issuance. For pre-approved plan submittals, the median we have measured across our own projects is 11–14 weeks — roughly half the calendar time.
The expedited path still includes site-specific review for setbacks, lot coverage, tree retention, stormwater, and energy compliance. What it eliminates is the architectural compliance review (structure, egress, fire separation, energy envelope), which is the longest single phase in a custom DADU permit.
The trade-offs nobody discusses
(1) The plan is fixed. Window placement, interior layout, and exterior cladding are all locked. Most pre-approved plans allow only a narrow finish-and-color palette. Owners who want a custom kitchen island or to move a bathroom will end up off the program.
(2) Site fit matters more than usual. A pre-approved plan that runs 28 feet wide cannot rotate on a 32-foot lot without violating setbacks. Roughly 25% of the parcels we evaluate cannot accept any plan in the catalog as drawn — they need a custom design.
(3) The royalty fee for the plan author is real (typically $4,000–$8,000) and is on top of the permit fees. The math still favors pre-approved when the plan fits, because the calendar savings translate to 3–4 months of earlier rental income.
When we recommend it
Rectangular flat lots in Seattle, 35 feet wide or more, with no critical-area overlay, and an owner whose goal is rental income rather than design statement. For that profile the pre-approved track is the right call almost every time.
