Snohomish County DADU options outside Seattle
Everett, Mukilteo, Lynnwood, Edmonds, Bothell, Mill Creek: where Snohomish ADU rules sit post-HB 1337 and what each city allows.
Snohomish is on a different clock than King
Snohomish County cities planning under the Growth Management Act had the same 2025 HB 1337 compliance deadline as King County cities, and most adopted compliant code on schedule. The cities most active for ADU work — Everett, Mukilteo, Lynnwood, Edmonds, Bothell, and Mill Creek — all permit two ADUs per single-family lot, with 1,000 sqft DADU caps and HB 1337's height baselines.
Where the variation lives is in design standards, tree retention, stormwater, and impact-fee schedules. Those differences materially change project cost.
Sources:Municipal Research and Services Center of WashingtonWashington State Legislature
Everett
Everett's code permits DADUs by right with relatively light design review. Lake Stevens / Mukilteo / Everett school-district impact fees are modest compared to King County peers — typically $3,000–$5,000. Tree-retention is enforced but workable. Permit timeline: 12–16 weeks median in our experience.
Mukilteo and Edmonds
Mukilteo enforces strict view-corridor and slope-density rules in the bluff neighborhoods overlooking Possession Sound — DADUs above a certain footprint trigger a view analysis. Edmonds is similar on the Sunset Avenue bluff and selectively in the Bowl. On flat inland lots in either city, the path is straightforward.
Lynnwood, Bothell, Mill Creek
Lynnwood is the friendliest of the three for ADU construction — flat topography, mature sewer infrastructure, and a permit office that runs reliably under 14 weeks. Bothell straddles the King/Snohomish line; the Snohomish portion follows Snohomish rules, the King portion follows King County and Bothell ordinances, which are different. Verify your jurisdiction at the address before design begins. Mill Creek's design standards (cladding, window trim, roof pitch) are stricter than its neighbors and add real design time.
Rental and resale context
Snohomish County rents trail King County by 10–15% on equivalent unit size, but land cost is also lower, which keeps cap rates competitive. A 700–800 sqft DADU in Everett, Lynnwood, or Bothell rents at $2,100–$2,500/month and pencils on cost bases 10–20% below the equivalent King County build.
