Seattle, WA

Snohomish County Liberalizes Backyard Cottage and Basement Apartment Rules

The Urbanist

By Stephen Fesler

Snohomish County’s long-awaited reform of accessory dwelling units (ADUs) has finally come to pass. Yesterday, the Snohomish County Council voted unanimously to pass a package of ADU regulatory reforms for both urban and non-urban unincorporated areas of the county where some 369,000 residents live — two-thirds of whom are in urban areas. Key highlights among the reforms are two ADUs per urban lot, elimination of owner-occupancy requirements, and no parking requirements for ADUs in urban areas. The package of regulatory reforms were much broader.
The pre-approved backyard cottage from Artisan Group on the City of Seattle's ADUniverse website.

The key adopted changes in the county’s ADU regulations (note that “AADU” means “attached ADU” and “DADU” means “detached ADU”) are as follows:
Stephen Fesler
Stephen Fesler
Snohomish County existing regulations versus the changes adopted on Wednesday.(Chart by Stephen Fesler)

Snohomish County did miss out on other reforms that could have gone further to encourage ADUs in urban areas, such as allowing two AADUs on single-family lots, increasing lot coverage, reducing setbacks, and allowing ADUs for duplexes and townhouses. The county also did not address genuine issues of ADUs being used in rural areas to create massive garages and avoid procedural and regulatory hurdles.

“if we’re looking at affordable housing, green housing, and increasing density, I think it’s critical that we can remove the restriction for the parking spots.”
Snohomish County Councilmember Megan Dunn, who represents District 2 (Mukilteo, Everett, and Tulalip).
Zoning map of Snohomish County. White areas are not under county zoning authority. Non-green areas are generally urban zones and greenish areas are general rural, resource, and farmland zoning. (Snohomish County)

During the meeting, there were four amendments to the base legislation that was considered with three of them passing. The county council passed back an amendment to the planning commission that would have allowed the creation of ADUs on smaller lots in rural, resource, and other non-urban zones that do not meet the applicable minimum lot size.

The first amendment that did pass addressed the maximum size of ADUs. This set the universal limit on ADUs at 1,200 square feet, not including other features likes basements and attached garages. It closely mimicked the original staff recommendation to the planning commission last year that had proposed limiting ADUs to 1,000 square feet in urban zones and 1,200 square feet in rural, resources, and other zones. The planning commission, however, pushed for a much higher number at 1,600 square feet, which is on the scale of many single-family homes. But the blended, single limit that the county council settled on brings the standard back to earth and better delineates it from a detached single-family home while promoting it as a more affordable alternative.

A second amendment passed that passed provides more flexibility in the location of DADUs on lots outside of urban areas due to site constraints like the location of existing environmental features and septic systems. It allows DADUs to be located more than 100 feet away from the principal single-family dwelling unit if the constrained site criteria are met.

The third amendment that passed eliminated parking requirements for all ADUs in urban areas. Councilmember Megan Dunn championed this amendment and argued for it during the meeting.

“Based upon research, occupants of ADUs typically own fewer cars than the average household and mandating parking will undermine efforts to boost construction of green, affordable ADU homes,” Dunn said. “Also, parking quotas thwart one of the cheapest forms of ADUs, which is garage conversions and this will also lower the cost because ADU parking spaces are estimated anywhere from $4,000 and $30,000 per spot. I think if we’re looking at affordable housing, green housing, and increasing density, I think it’s critical that we can remove the restriction for the parking spots.”

Council Chair Stephanie Wright disagreed with the policy proposal. She explained her position on why ADUs should have parking requirements claiming that the residents of ADUs “do have less cars, but they don’t seem to have no cars.”

In her full justification for voting against that amendment, Council Chair Wright said: “This [legislation] would require one car and what we’ve seen in [the urban] area is that even though people are using [public] transportation, tend to still have one car and actually a bigger need for parking because they are taking the bus and doing other activities, but like true Washingtonians we like to have our car for weekend recreation and our trips to Costco and other things.” She also added that she’s received many parking complaints in her urban district and was hesitant to support a parking reduction because there hadn’t been a parking analysis conducted.

Despite her disagreement with the policy, the amendment passed 4-1 and Council Chair Wright supported the overall legislation giving the county council an unanimous decision in favor of ADU reform.

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