County to pull back on D-ADUs on small rural lots

SNOHOMISH COUNTY— The county has to rescind its rule that allowed more rural landowners to be able to build a second, smaller house anywhere on their property after a state board determined in June this conflicts with growth management land-use rules.
Last year, shortly after the County Council loosened the rules on detached ADUs in response to public interest, the anti-sprawl organization Futurewise challenged it to the state Growth Management Hearings Board.
Soon, detached accessory dwelling units (ADUs) on rural lots under 5 acres will be prohibited again.
The changes, though, do not affect the ability to build a detached ADU on larger rural lots or take away being able to build a detached ADU more than 100 feet away from the main house.
The County Council is expected to decide by the end of the year.
One of the goals behind detached ADUs was to encourage affordable housing in low-density areas.
The board ruled, though, that allowing more detached ADUs on rural land conflicts with the county's own plans to redirect and slow down population growth trends away from rural areas, and also it "fails to protect designated agricultural lands," the state board wrote.
Futurewise's objections center on the idea this allows more housing density in rural land, and that developments could damage rural space.
The group also objects to a condition the County Council approved in 2022 that a detached ADU doesn't have to be built within 100 feet of the main house. It considers far-flung houses disruptive to farmland, writing to the county planning commission last month that without a restriction it "will be easier to site detached ADUs in rural areas and on natural resource lands” including salmon environment.
Supporters of removing the 100-foot rule said this will retain rural character, not erode it.
The organization believes that “the most affordable ADUs are internal and attached ADUs,” Futurewise’s director of planning and law Tim Trohimovich said. “We support allowing internal and attached ADUs in rural areas and, with appropriate conditions, agricultural and forest lands.”
In the same June decision, the state board denied Futurewise's call to invalidate the county's entire rulebook allowing rural detached ADUs. Futurewise contended that allowing detached ADUs would lead to a proliferation of them on farmland and woodland — a backdoor flood of urban growth on rural lands. The board shot that down as a speculative argument.
The County Council must decide on altering the rules to meet state compliance before the state growth board’s deadline of Dec. 13. What they approve could be appealed to the state board for more rounds of discussion. If no changes are made by the Dec. 13 deadline, the overarching penalty is that the county would become disqualified from certain state funding grants.