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Ten steps to permitting an ADU

Ten steps for planning, designing, and permitting an ADU
Building an ADU is daunting. Here’s a quick sketch of the chronological steps to get ready to build an ADU on your property: The Design Phase
  1. Brainstorm project goals and scope with funders/partners
  2. Talk to municipal zoning office about the project to determine feasibility; try to uncover any major regulatory design/cost obstacles that you’ll have to overcome
  3. Rough sketch some ideas and think through your top design objectives with funders/partners
  4. Identify architects, builders and sub contractors (ideally, you want to have identified a general contractor, as well as your plumber, mechanical, electrical subcontractors)
  5. Architect  and homeowner draw up schematics for consideration based on your rough sketches and your objectives
  6. Meet with architect, builder, and subs to talk through objectives and schematics to get their input
  7. Architect refines schematics with homeowner and contractors. I’d recommend having your architect develop a 3D model in Sketchup.
  8. Develop permit-ready drawings for zoning and building office
  9. Sumbit plans for permit. Pay permit fees. Go back and forth with permit office until the plans pass their planning/zoning code and building code criteria.
  10. Permit issued and then you can break ground

This design phase can take as little as a week, or many years. My ADU took three months to design, going back and forth with my designer through fifteen schematic drawings. 1-5 months is an average time frame for this phase.

My advice: Take your time with the design. Go back and forth with your designer and your builder, and make sure you’re very happy with every detail of the design. Build a 3D model: your ADU will look a lot like your 3D model, so spend some time lounging and walking around inside your 3D model.  This is a huge financial investment- it is worth the extra energy up front to dial in your design before you submit it to the permitting office.

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

9 comments on “Ten steps to permitting an ADU

  1. Pingback: Building Design and Construction Process – Step by Step | Accessory Dwellings

  2. Stephanie Lynn (@sefatwit)
    August 28, 2012

    Hi Kol – do you know, off-hand, what the easement rules are for ADUs in R5?

    • kolpeterson
      August 28, 2012

      @sefatwit For the basics, read

      In Portland, ADUs must set at least 5 ft from the rear and side property lines. There are nuances to these regulations regarding 1) eaves within the setback 2) alley dwellings, which can sit on the rear lot line and 3) certain garage/ADU conversions, which can be grandfathered in even if they sit within the 5ft setback.

      • Martin John Brown
        September 6, 2012

        kol (actually eli might be a good person to ask on this??) isn’t it always possible to go for a variance, no matter what the rules say? It’s expensive, and not guaranteed, but a few years ago I believe that ADU-related variances were being approved regularly.

  3. helgaiden
    September 6, 2012

    Hi. I’m looking at a home that has some issues here in riverside, CA. 2 big things, the sdu is detached but according to the city, it has to be demolished. Its a garage converted to a big open living room wth an apartment below it.
    -Says that secondary dwelling units cannot be built in the backyard setback. I don’t understand this can you please clarify it?
    -says a detached second dwelling should have a minimum building wall seperation from the primary dweling by 15 feet. (Apparently it doesn’t)!

    I also read that if the two strtuctues share a common roof, the SDU will be known as an addition. The two buildings are connected by a walkway/bridge from the top story of the primary to the converted 2nd floor garage on the secondary. If I find a way to build around that walkway, make it into a hallway basically, and connect the roofs….that should make it okay or no? Will that help with anything else?

    • kolpeterson
      September 6, 2012

      helgaiden, unfortunately, that sounds like a common scenario to me.

      If the garage was permitted legally initially for a particular use, you can probably justify keeping it there if you don’t change that use.

      If the owners wished to change its use to an SDU (which I’ll now refer to as an ADU- see the post “The many and confusing synonyms for ADUs“), then the city probably needed it to adhere to more restrictive zoning requirements regarding setbacks from property lines and other buildings. Unfortunately for you, the owners did not go through these steps, which leaves you in the position of retroactively trying to make their ADU comply with the proper codes.

      That’s an uphill battle that you probably won’t win.

      However, you may be able to claim the breezeway as a connective architectural structure and therefor call the ADU an “addition”, which may effectively resolve the zoning issues and allow you to effectively have a secondary living space. But, you that will not be considered an “ADU”.

      Or, easier still, you can simply leave it alone as a “garage”. Non-permitted ADUs in SoCal are VERY common, I suspect.

  4. Martin John Brown
    September 6, 2012

    helgaiden, have you tried speaking with architects or contractors who have actually completed legal ADUs in Riverside, to see what they think? There might be ins and outs we on this site aren’t aware of. Please let us know what you learn, and consider contributing to our nascent database of ADU regulations…. Thanks!

  5. helgaiden
    September 6, 2012

    I do plan on speaking with the proper people if my offer on the home is accepted. I plan on submitting a lowball offer on it given that the likely scenario is demolishment, but as an REO thats been on the market nearly a year, im hoping the bank just wants to wash their hands of it and counters within 10k of the offer im planning on. They want 150k, i want to offer 110k. The “garage/ADU” was built with permits, but it looks like the permits werent complete, at least according to my mom who went the city to ask about this property. Heres a list of the permit stuff to check out:

    Id love to keep it, even if converting back to garage/storage (the bottom story dwelling/apartment doesnt have many walls inside) but i wonder if the uphill battle would be worth the cost or just demolish and save up to try again and have it built right. If they accept my offer, ill probably be able to figure that out. Right now the “current owner” is not allowing city officials to inspect it, likely in fear of them finding more violations to fine them with (which i dont think is likely but still). So any progress with that appears like it’ll have to be made once an offer is accepted, hopefully mine.

  6. Pingback: Building design and construction process – step by step | Accessory Dwellings

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This entry was posted on October 29, 2011 by in Design & Build and tagged , .
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