Go Far®ADU & DADU builder · Bothell
ADU & DADU builder for Bothell.
Bothell straddles the King–Snohomish county line with a university, the North Creek tech corridor, and some of the strongest small-rental demand north of Seattle — and its ADU code is among the more generous in the region, allowing detached cottages up to 1,200 square feet. Go Far Construction builds permitted, finished ADUs across Bothell: ground-up backyard cottages, basement apartments, garage conversions, and attached units, from a family-owned, licensed Washington general contractor based fifteen minutes west in Lynnwood.
Washington’s ADU law — HB 1337 — sets the statewide floor of two accessory units per lot, and Bothell’s code meets it with room to spare: two ADUs on most residential lots, detached cottages up to 1,200 square feet — two hundred beyond the 1,000-square-foot minimum the state guarantees — detached units up to 30 feet tall (33 feet over an existing accessory structure), and DADUs exempt from the usual cap on accessory-building lot coverage. ADU impact fees are capped by state law at half of what a primary home pays. Our ADU vs. DADU guide walks through which route fits which lot.
On budget: basement ADU conversions and garage conversions in this market generally land between $100,000 and $250,000 depending on the starting condition of the space, while a new-build detached cottage typically runs $250,000 to $450,000 including site work, utilities, and soft costs. The full math lives in our ADU cost guide and DADU cost guide — and few markets make the rental side pencil like Bothell, where university students, North Creek and Canyon Park tech workers, and downtown’s restaurant row keep small rentals in constant demand; ADU financing options covers how owners fund the build.
We build every route to a second unit: basement conversions under Maywood Hill and Shelton View split-levels, garage conversions, attached mother-in-law suites, and ground-up DADUs in Canyon Park, North Creek, and Westhill. Wherever the parcel sits — the King County side or the Snohomish County side — permits run through the City of Bothell; we prepare the application, carry fees in an itemized written price, and meet every inspector on site, as on all our Bothell projects.
What we build in Bothell
Bothell ADU questions
How much does it cost to build an ADU in Bothell?
Basement ADU conversions and garage conversions generally land in the $100,000–$250,000 range depending on the starting condition of the space. A new-build detached ADU (backyard cottage) typically runs $250,000–$450,000 including construction, site work, utility connections, and soft costs. Every project gets an itemized written estimate before design is finalized.
How many ADUs does Bothell allow on a lot?
Two on most residential lots, in line with Washington’s statewide ADU law, HB 1337. Lots that already contain middle housing, and lots constrained by critical areas or their buffers, are generally limited to one. Exactly what fits on your parcel still depends on zoning, coverage, and setbacks, so we confirm the numbers with the City of Bothell before design begins.
How big and tall can a DADU be in Bothell?
Bothell allows accessory dwelling units up to 1,200 square feet — more than the 1,000-square-foot floor state law guarantees — with detached units up to 30 feet tall, or 33 feet when built over an existing accessory structure such as a garage. Detached ADUs are also exempt from the usual cap on accessory-building lot coverage, and conversions of existing space can sometimes exceed the size cap with the city’s approval.
Do ADUs in Bothell pay impact fees?
Bothell charges impact fees on new dwelling units, but under state law an ADU’s impact fees are capped at no more than half of what the primary house pays. We carry permit and fee costs as line items in your itemized written estimate, so the all-in number is on paper before design is finalized.
Plan your project
Costs, rules, and timelines for Bothell ADU projects: ADU costs · DADU costs · Washington’s ADU law · ADU timelines · ADU financing · Lynnwood ADUs · Kirkland ADUs · Shoreline ADUs · our Bothell page