The Seattle City Council unanimously approved legislation that eases citywide regulations on the construction of accessory dwelling units on Monday, July 1.

The legislation gets rid of the off-street parking requirement for ADUs, allows attached and detached accessory dwelling units (AADUs and DADUs) to exist on single-family lots, introduces a floor-area-ratio (FAR) limit to single-family zones, eliminates the owner-occupancy requirement to build an ADU, increases the maximum size of DADUs from 800 to 1,000 square feet, allows design flexibility to preserve existing trees, and also requires a future demographic survey on ADU owners and occupants.

Councilmember Mike O’Brien, who had been pushing the legislation’s passage for more than four years, made a few clarifying remarks before the council went to a vote.

“The intent here is to make it easier for folks to build accessory dwelling units, whether those are attached or detached,” O’Brien said. “The legislation is based on well over four years of feedback on what people in our communities would like to see and what kind of flexibility they would like to have or what kind of barriers that they have today.”

O’Brien also said ADUs and DADUs can still only cover 35 percent of a single-family lot, and the remaining 65 percent must be left open. He stressed that the legislation does not loosen tree regulations, and he suggested he would support a review of the existing tree code.

The city council discussed three amendments before passing the legislation.

Councilmember Abel Pacheco’s amendment for bike parking spaces passed, as did O’Brien’s for a yearly short-term rental activity report. Pacheco’s amendment on bike parking spaces allows additional space for designated bike parking spots, exempting 35 square feet of floor area from the FAR limit.

O’Brien’s amendment added language to the legislation that says if the council determines too many ADUs are being used for short-term rentals, the council has the option to add restrictions in the future.

Councilmember Lisa Herbold’s amendment to restrict construction of a second ADU did not pass. It would have required residents with ADUs to own their single-family home for at least a year before building a second ADU. The council voted 7-1 to strike it down.

Herbold brought this amendment to the sustainability and transportation committee on June 18, where it first failed to gain support.

“I am still concerned about the speculative market shifting to take advantage of these new regulations,” she said. “So, the second amendment is focused on a speculative market that will flip these units in such a way that will have a displacement impact on renters.”

O’Brien and Pacheco, who were both at the sustainability and transportation committee meeting, voiced their opposition to the amendment again, saying they do not want to stifle ADU construction.

“I hope that we see two accessory units on a lot of single-family lots, because I think that’s going to be good for our neighborhoods,” O’Brien said. “It will allow new opportunities for people who can’t afford in these neighborhoods to live in those neighborhoods and that may help the homeowner too.”

“I am concerned that this amendment would make it more difficult and costly to build a second ADU,” Pacheco said, adding there is language in the legislation that deals with how the council can choose to address the “speculative market” in the future.

Councilmember Kshama Sawant agreed that something should be done to “speak up against speculation.”

“Absolutely, we have to be pushing back against the for-profit market,” she said. “But, as the other council members have stated, the data is showing that speculation is very rampant in the building of towers of luxury units and rowhouses. I have not seen any speculative ADU bubble anywhere.” 

In the council’s closing remarks, Pacheco said he’s lived in two ADUs, one in Wedgwood and another in Wallingford, and he would not have been able to live in Seattle without the more affordable option. He wanted to address comments he has heard about renters; that they do not care as much as homeowners about the neighborhoods they live in.

“As a renter myself, I show up to work every day to work with a desire to make my community better. Let me be clear, we’re all neighbors, and it’s time that we show each other the respect that we each deserve,” Pacheco said.

O’Brien, who will be leaving the city council at the end of his term, answered a question he said he gets a lot. Why did it take four years to pass the legislation? He predicted 2,400 ADUs will be built in the next 10 years. The final environmental impact study for the proposal predicted 1,970–4,280 ADUs would be constructed from 2018–2027, depending on regulation changes. However, the legislation was passed in 2019.

“I think it’s a fair question, because it’s a lot of work that people have done for a relatively modest shift in what we predict will happen in our neighborhoods,” O’Brien said. “But I also think the reason folks have engaged on such a deep level is because there’s a fundamental question on what we are going to do in our single-family zones and what’s appropriate.”