Photo of an architect's blueprint with a pen and the caption "Applying for an ADU Permit"

You’ve researched accessory dwelling units or ADUs extensively and you’re ready to build. But, the city or town you live in requires you to get a permit before you can start construction.

How do you apply for an ADU permit? (Still researching? Check out our other ADU articles here.)

To apply For An ADU Permit, Follow These Steps:

  • Have documents such as architectural drawings, floor plans, etc.
  • Apply for the permits
  • Undergo permit review
  • Receive the final design
  • Start building

The number of permits you need will vary, such as a building permit versus an electrical permit.

The steps you take to obtain these permits depend on the rules in the city or state in which you live.

Keep reading for ADU permit information that can help you get started with your ADU plans.

The Types Of Permits You Usually Need To Build An ADU

When we’ve talked about getting permits for your ADU on the blog, we’ve usually referred to “permits” as a plural word.

That’s because rarely will your city or town require just one permit. It’s typically several.

Here is an overview of the types of permits you will have to have ready before your ADU can proceed.

Building Permit

This is the most significant permit, as it’s essentially permission from your neighborhood that you’re allowed to build the ADU.

The building permit will include all the ADU restrictions as imposed by your city or town, such as limits on size, height, and features.

Before you begin designing your ADU (more on this in the next section), you must be aware of the restrictions on ADUs in your city or town.

It would be a waste of everyone’s time and effort to design an ADU that’s larger than what’s allowed only to try to get a permit for it.

You’d be turned down and have to go back to the drawing board.

If your dwelling is under the jurisdiction of a homeowner’s association, you must be clear on the HOA’s rules about your ADU as well.

If their rules clash with the city or town’s rules, we recommend speaking to someone in your HOA or a city/town representative to get the rules straight.

The safest course of action would probably be to check with all known organizations in your local area that may or may not affect your property and your ability to build an ADU.

Some of these might include:

  • Your HOA (if you have one)
  • City building department
  • County building code-related sources
  • State-level ordinances, building code, and any requirements

I would also suggest not going off what other people tell you. Get it from the horse’s mouth – either written in the code itself or in writing from your local/county/state building departments on what you’re able to do.

That includes us here writing this article, what contractors tell you, and anyone else. In my own journey here to build an ADU, so much has been thrown around in terms of what you can and cannot do, it’s just got to be in writing.

Photo of a desk with a clipboard and laptop, with two people shaking hands across it. Getting an ADU permit may require meeting with someone to find out what's required.
It’s worth the effort to find out who you need to talk to and plan your ADU right.

Electrical Permit

Whether yours is an above-garage ADU, a converted basement ADU, or a freestanding unit, you expect it to have electricity. So too will your guests anticipate access to basic amenities like lights and climate control.

This will require you to get an electrical permit drawn up.

The electrical permit will outline the required power your ADU needs as well as where that power will be sourced from.

You might have to contact a local electrician to help you put together the electrical permit or guide you in the direction of someone who can help.

Location Permit

In some parts of the United States, where you plan on building your ADU will subject you to a location permit.

For example, if you’re in a landslide zone, a geohazard zone, or even a coastal zone, you’d need a location permit.

Outside of these special areas, a location permit is usually not required, but we recommend reading up on the rules in your city or town to be sure.

Additional Permits

Besides the above permits, in special instances, other permits might be required to build your ADU. These include:

  • Address assignment request: An address assignment request is so your main dwelling and ADU technically have different addresses. Obtaining an address assignment request isn’t free and can cost a few hundred dollars depending on where in the country you live.
  • Site-specific permits: Is building your ADU going to impact your neighbors at all? That’s not up to you to decide. If your neighbors deem the building of your ADU an interruption, then you might have to get a site-specific permit. As an example, if you wanted to build near an easement, some cities demand you apply for an easement permit.
Photo of a single post with two mailboxes. One ADU permit you may want to apply for is a separate address assignment.
If you plan to rent out your ADU, a separate address will make life easier for everyone.

How To Apply For ADU Permits

Before you apply for your ADU permits, you should have already arranged the loan pre-approval (if required for your project).

You must have also applied for zoning approval if zoning laws apply in your city or town.

With those steps taken care of, here’s how to apply for an ADU permit.

Have The Right Materials

Applying for ADU permitting will require a variety of materials.

You will be expected to provide a list of the licensed contractors you’re currently working with or plan to work with.

You should have already contracted an architect to draw a blueprint of the ADU.

Going back to what we mentioned earlier, you must be aware of all the ADU rules and restrictions in your city or town before the architect creates the drawing.

Otherwise, that drawing of your ADU may very well be unusable.

You may decide to work with that architect for the final design and follow-through of your ADU, but that’s something to figure out a bit later.

The site survey is another important document to have ready for your ADU permit approval. You also want to include the architect-drawn floor plans.

Even if you have one specific floor plan in mind, it’s not a bad idea to get several floor plans drafted in case the first one isn’t feasible.

A shipping container could make a perfect ADU if it’s permitted in your location. Photo by Jed Owen on Unsplash

Apply For The Building & Electrical Permits

If you’re not sure whether you need the extra permits we discussed in the last section, then start with the required building and electrical permits and work your way out from there.

You can contact your building officials to ask about the extra permits.

Add Any Extra Permits If Required

Once you’re sure whether you need additional permits as part of your application, you can include these as well.

Wait For Permit Review

Now you will send all your paperwork and documentation to your local building department.

They’ll go over everything, including the ADU design. This can take some time, so be patient.

If you’re asked to make changes to your plans, then you’ll be expected to do so.

Receive The Final Design

Otherwise, after the building officials from your city or town approve the design of your ADU based on the permits, that design is now final.

You must follow the final design when constructing the ADU, as going against it could be considered breaching the permit.

In some instances, you might have to go back and adjust your contractor bidding and even your loan approval amount based on the final ADU design.


Applying for an ADU permit first requires you to gather materials like blueprints, zoning approval, floor plans, and approved contractors.

Remember that once your ADU permits are approved, building the ADU to those specifications is paramount.

Best of luck!

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