Accessory Dwellings

A one-stop source about accessory dwelling units, multigenerational homes, laneway houses, ADUs, granny flats, in-law units…

Incremental Updates for ADUs for 2020

Here’s some notable updates for those interested in ADU minutiae in the Portland market and beyond.  It contains a mashup of new information that will be of interest to ADU advocates anywhere. 

ADU Permit Numbers

First of all, I wanted to share the latest chart of ADU permits issued in Portland. As I predicted last January, 2019 saw a significant drop in permits issued.

I speculated on some reasons for this drop in permits in 2019 in a previous post, in case you’re interested in why there’s a drop this year. Also, I used a different database for my query this time, so the annual permit numbers varied a little bit from my previous post. But, the total permit numbers are roughly the same.

According to this new database query, there’s 2,487 ADUs completed, with another 652 under inspection. 

The MLS in Oregon now includes ADUs as a standalone database category

RMLS is the Regional Multiple Listing Service (RMLS™) serving approximately 14,000 real estate professionals in over 2,600 offices throughout Oregon and Southern Washington. 

Their system has just added a new field to the database, which allows real estate professionals to tag their property as having an ADU. Now, real estate agents will be able to post and search for properties systematically that have an ADU. 

The new RMLS database field that allows subscribers to query whether a property has an ADU or not.

This small update to the RMLS database represents another leap forward for ADUs, which are increasingly gaining institutional acceptance in seemingly incremental steps like this.

This one itsy-bitsy, tinie-winie, little database update allows researchers, appraisers, buyers, and sellers anywhere in the country, to have a much more sophisticated potential to easily analyze, assess, value and buy & sell properties with ADUs in Oregon. 

Other MLS managers and administrators in CA and WA and elsewhere would be smart to follow suit. 

To show the power of this tiny little update in the MLS database, here’s a custom new report that of the 58 properties for sale on December 18th, 2019, that were tagged as having an ADU. 

I was surprised to see a) how many properties with ADUs were for sale and b) how many of them were new construction.Based on this database search, I can now see there is a new class of whole-site redevelopment new construction that includes ADUs, now coming on the market.  In general, the audience that I deal with as an ADU consultant and educator are homeowners who aren’t building ADUs to sell the property. So, this report was enlightening.

Notably, there were some false positives in this list of 58 properties, due to human error. But, that will get ironed out in time as this checkbox gets used more.

Mapping the Spread of ADUs in Portland Over a Decade

Viet Nguyen put together this interactive, time-lapsed, annualized map of how ADUs have spread geographically over the last decade in Portland. Click on the years at the bottom of the chart to see where ADU permits were issued that year. 

There’s two elements that I noticed in reviewing these annualized maps. 

  1. It appears as though ADUs tend to cluster a bit in the Portland market. 
  2. The geography of ADUs has dispersed over time, spreading further north and east in recent years. 

ADU Open Doors- April 23rd and 24th, 4-8pm

I’ve partnered up with Propel Studios to put on a new event this year called ADU Open Doors, in which anyone in Portland can open up an ADU for showing. And, anyone may attend. And, it’s free for all. It’s being held in conjunction with the next ADU Academy.

Check it out and plan to participate as a host or attendee


SDC Fees for ADUs in Portland Continue to Rise

Here’s the breakdown for a recent ADU broke down for one detached new construction project that was shared with me. 

System Development Charges

Parks-                                               $9,682

Portland Bureau of Transportation: $2,697

Water-                                             $4,593

BES (Sewer)-                                    $5,533

Total-                                             $22,505

The system development charge fees are quite expensive–$22K in this case; it’s a good thing that good thing most applicants don’t have to pay them! In 2018, the City of Portland decided to waive SDC fees for ADUs except if the applicants wished to have a short-term rental on their property. In this case, the applicant wanted to leave open the option to do a short-term rental, and thus, they incurred the $22K SDC fee. 

Even beyond the $22K in SDCs, the total permit fees added up $36,789.98. That’s above and beyond the architectural design costs, engineering costs, and land use surveys that may be required in order to submit a set of plans to the City. That can easily add up to more than $20K. So, that would total $56K before breaking ground and getting into the costly phase of construction. 

These numbers clearly still represent a formidable barrier to ADU development for the average homeowner. It’s a good thing there’s some major innovation happening on the ADU Financing front. 

That’s a good segue!

Video Recording of the two ADU Sessions from the last Build Small, Live Large Summit in November, 2019

There were two sessions at last year’s summit that focused on ADUs. One session focused on ADU financing; the other session focused on nationally-relevant ADU updates.

2019: The Year of Progress in ADU Finance Innovation

The Urban Sustainability Accelerator at Portland State University funded this recording. 

What’s New with ADUs? Legislation, Development Costs and Valuation

This session was funded by my iPad. Forgive the quality.

About Kol Peterson

Kol is an ADU consultant, advocate and author of Backdoor Revolution: The Definitive Guide to ADU Development. Read more here: and learn about building your own at Email at

4 comments on “Incremental Updates for ADUs for 2020

  1. Helen Buckholz
    January 29, 2020

    why is it so hard to find ADU contractors in California, it seems every add refers to other states.

  2. Pingback: Roger & Martha’s tiny house — economical, artistic, and prefab | Accessory Dwellings

  3. Pingback: West Coast Cottage Reforms Lead to Explosive Rise in Permits - Sightline Institute

Comments are closed.


This entry was posted on January 8, 2020 by in News and tagged , , , , .
%d bloggers like this: