Permitting Your Portland ADU: A Step by Step Guide

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Permitting Your Portland ADU: A Step by Step Guide

Whether you’re converting an attic or garage, remodeling an existing space, or constructing a new ADU, you’re going to need a permit from the City of Portland before you can begin construction. 

In a nutshell, your ADU permit serves as proof that your new space meets the appropriate building codes and satisfies specific safety requirements laid out by Portland’s Bureau of Development Services (BDS). 

And, as with any bureaucratic procedure, obtaining a building permit can be a complex, lengthy, and often overwhelming process. But we’re here to help simplify it: part of our job as ADU designers is to help you with the ins and outs of the building codes and permitting procedures you’ll need to have in place before you can build. 

In this post, you’ll find a pared-down summary of the major steps laid out in the BDS’s official guide to residential ADU permitting (link below), so you can better prepare yourself for the work ahead. 

Note: links are current as of December 23, 2021. This post does not contain all of the required documents you’ll need to get your ADU permitted and serves only as a starting point in your research to get you better acquainted with the process. When you’re ready to get started for real, visit the official Bureau of Development Services ADU permitting guide here

Before you begin the permitting process… 

It helps if you have some ideas for ADU designs –– or at least have a design team on your side (and if you don’t, contact us). Your design team can help you come up with a site plan and strategy for your property (or give feedback and advice on the plans you came up with yourself), research what your property allows, find contractors, source materials, recommend appliances, and much more. 

Now that you’ve got that handled, you’re ready to get started with the hard part. 

Step 1: Research your property to understand what exactly you can do with it

First off, you need to check the permit history of your existing house. If you’re wanting to turn your attic into an ADU, but the attic wasn’t permitted, you’ll need to legalize it before you can do anything else. 

You’ll also have to double-check the appropriate design and zoning standards that apply to the type and size of ADU you want to build (things like height allowances for instance). If you’re planning on building a detached, covered ADU, make sure you read this worksheet. 

Other elements you’ll need to take care of in this step:

Step 2: Design your ADU (or hire us to design it for you) 

In a nutshell, there are three ways to go about ADU design: 1. you do all of it yourself; 2. you do some of it yourself, or; 3. you hire a designer and do none of it yourself.

If you decide to go the DIY route, you have the advantage of having full control over the development of your space. The downside(s) is that you’ll need to figure out the steps in this process by yourself, research and understand all the appropriate building requirements, and make all the not-so-obvious decisions about your space on your own (e.g. how close your toilet is allowed to be to your bathtub, or how high your ceilings can be to comply with building codes). 

Alternatively, you may want to have control over the design but hire out a design consultant to verify your work and make sure everything is compliant with the necessary codes and requirements. Think about it as if you were a writer hiring an editor to double-check your grammar before submission to a publication. (And yes, we do consulting, too.)

Finally, you can entrust the whole process to a design team, who will work with you to ensure the design satisfies your unique vision and stays compliant with all the little things you never knew you needed to think about. Your design team can also link you up with contractors if you haven’t found them already, help you source materials, and recommend appliances to install further down the road. 

Step 3: Talk to a Portland planning expert to get extra help with the process

The City of Portland has city planners, building code and engineering reviewers, permit technicians, water experts, and transportation experts on staff to help answer any questions you may have about any step of the process while you’re still in the beginning phases of your project. You can schedule your free 15-minute consultation with an expert here. 

If you have questions about sanitary lines, sewer lines, or stormwater lines, you can contact Environmental Services at 503-823-7761. 

Step 4: Fill out your ADU permit application and submit your documents online or in-person 

If you plan on building a new, detached ADU, you’ll want to follow the guidelines for a New Single Family Residence. 

On the other hand, if you’re planning on converting an already existing space, you’ll need to satisfy a few other requirements, like complete a building permit application and have a site plan and architectural plans in place. 

Other important links you’ll need in this step: 

Step 5: Check your review status and make corrections

Once you submit your permit application to the City, you can check the status of its review periodically to see where it’s at and find out what else you need to do to push the process along. 

For more information about the permit review process, visit this page

To learn how to appropriately format and submit corrections, read this. 

Step 6: Time to (finally) obtain your ADU permit

Once your permit application has been approved (or not), you’ll receive a notice via email or phone, as well as detailed instructions for how to pick up your permit and pay all the necessary fees. 

Note: your permit won’t actually be issued or valid until you pay all the fees required. 

Step 7: Start construction on your ADU and prepare for inspections

Once you begin building, you’ll need to pass several inspections that ensure the proper measures are being taken during construction. 

Sometimes, you’ll even need to pass certain inspections before you can start building –– think erosion control and tree protection on the property. And, depending on the results of those pre-construction inspections, you may need to make and submit a few more corrections before you can break ground. 

Scheduling an inspection with the BDS 

You can schedule an inspection Monday through Friday from 8:15 am – 3:45 pm, by phone (503-823-7388) or email

Time to get dreaming about your new ADU

We hope we’ve given you some things to think about as you begin the task of permitting your ADU plans. 

No matter where you are in the process, the designers and strategists at Consolidated Living can help you reach your goal on time, on budget, and in line with your vision. 

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