Accessory Dwelling Unit by Chrystine Kim, NEST Architecture and Design

Beyond Backyard Cottages: Putting a number on the cost of doing nothing.

Matt Hutchins
3 min readJan 15, 2018


First off, THANKS to all the 500 plus people who signed MOAR’s (More Options for Accessory Residences) petition to sensibly address the need for Seattle to create more dwellings in our Single Family Zones. We made more than HALF of all the comments the City received.

The City has now published the EIS Scoping Report, and is adding a third alternative. They’ll study the impacts, tweak the levers, and produce the Final EIS. There’s lots to feel positive about (more about that below), but let’s start with one truly bad suggestion:

‘Based on scoping comments, we intend to introduce MHA requirements in one action alternative that apply when someone creates a second ADU.”

That is potentially a new fee due at permit issuance of an extra $5000-$15000, depending on the square footage and neighborhood of the new ADU. If the ordinance’s objective is to create more ADUs, this penalty is going to guarantee very, very few homeowners are ever going to build that second ADU, or do it legally. Keep in mind, Seattle is simultaneously entertaining development impact fees, a double whammy of upfront costs.

Otherwise, the EIS will study effects of reducing permitting time and development costs. It will study extra height (for green roofs for example) and extra flexibility, including having both possible ADUs be attached to the primary residence. The city will begin studying using Floor Area Ratio to limit McMansions (that is a big deal — here’s how Portland is addressing it).

The Scoping Report tosses some old red herrings overboard, eliminating noise analysis (covered under current code), dialing up lot sizes (contrary to the objective of creating more ADUs). Complaints about utilities and services will mostly refer back to the Comp Plan EIS already done.

The Scoping Report hints at some other incentives outside the Land Use Code ‘for reducing the costs for homeowners to create ADUs and incentivizing creation of rent-restricted ADUs for low-income people. These potential strategies are not included in the alternatives but may be discussed as mitigation measures to address potential impacts identified during the environmental analysis.’ Since the cost of an ADU is a greater impediment than Code, having the City thinking about financing challenges could be huge (and why MHA at the ADU level is nuts).

The EIS will try to measure the effects of owner occupancy requirements, potential rental income, property tax rates, short term rentals. There is quite a bit of hedging — calling to vary parking requirements, household sizes, responses to lot characteristics, quantifying neighborhood effects.

Owner occupancy is still clearly the heaviest lift here politically, because it stirs up this weird toxin of xenophobia, suspicion of capital and profit, fear of transients and tenements, and property value tribalism which has fueled the perception of renters as second class Seattleites (strange since renters are already the majority of the population). I’m looking forward to some real analysis showing how many potential dwelling units are stalled by owner occupancy.

Nevertheless, the FAQ makes the critical point that owner occupancy is a UNIQUE requirement for residential property owners with an ADU. There are no restrictions on owner occupancy otherwise in residential zones in either for Single Family or Multifamily. Why would lifting it here fundamentally change our city? We trust our neighbors to rent their houses, so why not their basements too?

Finally, the Beyond Backyard Cottage petition had some far reaching recommendations, and it isn’t surprising that the City isn’t taking them up with this effort. But in the the context of Seattle’s HALA policy, it is great for the city to see a vocal constituency in support of re-evaluating Single Family Zoning* even if those ideas were clearly beyond this Environmental Impact Statement.

Thanks, and stay tuned!

*One of the ‘highest impact recommendation’ of the HALA report was to “Allow for more variety of housing types, such as small lot dwellings,cottages, courtyard housing, duplexes and triplexes, in Single Family zones”