ADU Permit Process Simplified: Your Guide to Easy Approval

The ADU permit process in Los Angeles is simple and something every homeowner should consider. I’ve worked on multiple ADU projects for clients and I also have first-hand experience building two of my ADUs and a JADU (Junior Accessory Dwelling Unit) for my parents. 

The ADU permitting process involves learning about your local jurisdiction’s ADU laws, getting a general quote for construction and securing financing, getting plans drawn by a design professional, and finally, submitting them to the city for approval. In this blog post, I’m going to help you get clear on the ADU permit process and approval.

If you’re a homeowner in Los Angeles, building an Accessory Dwelling Unit is a smart investment. ADUs are known as granny flats, in-law units, tiny homes, or backyard cottages. They offer several benefits, including additional rental income, increased property value, and the potential for housing family members. 

They came about as a response to the housing shortage, empowering homeowners to build homes in their backyards and allowing us to legalize our garages as living spaces to rent out and earn extra income. However, navigating the ADU requirements and approval process can be daunting and confusing. So let’s start with the basics.

Understanding the Basics

Before diving into the ADU permit and approval process, let’s cover the basics:

What is an ADU? An ADU is a secondary dwelling unit located on the same property as a primary dwelling, in a single-family dwelling or multi-family property. These are independent homes with their private entrance and full kitchen. Junior ADUs can have a (smaller) efficiency kitchen. Oftentimes you get a new address and can separate the utilities.

What are the types of ADU: Los Angeles allows various types of ADUs, here are the most common ones:

1. Detached ADUs: These can be new construction or a conversion of an existing structure, typically a garage or other unused accessory structures such as a rec room, patio, or basement
2. Attached ADUs: These can also be new additions or conversion ADUs such as a garage attached to a primary residence or apartment

Where are ADUs allowed? They’re allowed in single-family homes and multi-family properties. 

What is the maximum number of ADUs allowed? In a single-family residence, you can build one detached ADU and a JADU (converting existing square footage within the main house). In multi-family properties, you can build two detached ADUs and one attached ADU. The maximum size of an ADU is 1,200 SF and for a JADU is 500 SF.

For more information on ADUs and JADUs, I’ve covered these topics extensively in these related blog posts:

Guide to an ADU in a Single-Family Property
Guide to an ADU in a Multi-Family Property
Building an ADU: Design & General Requirements
Guide to Building a Junior ADU

Now, we can move on to the first step in the process:

Checking ADU Regulations and Zoning Laws

The first step in building and permitting an ADU is checking if your city allows for ADUs. 99% of the time they do. The easiest way to get in touch with your city’s planning department is to type on Google “Your City ADU laws” or “Your City Planning Department”. Another similar search is to reach out to your city’s Community Development Department (which includes Planning and Building).

Here is an easy and quick way to check what zone you’re in:

1. Go to the Los Angeles County Assessor’s Website and type in your address
2. Select the appropriate address. The website will display your property’s information such as Assessor Parcel Number (APN/AIN), lot size, number of buildings, size of the building and number of bedrooms among other things
3. Scroll down to Building and Land Characteristics (you may need to click on the + button to open it up
4. Look for Zoning. If there is an R then congratulations, you can build an ADU!

There are two layers of regulation: State Law (broad framework, less strict) and local government (each city may have unique requirements so it’s always important to check with local city regulations and restrictions). Please note that no city or local government can preclude you from building an ADU of at least 800 square feet and 16 feet in height. 

Zoning Requirements for ADUs

Conforming to zoning regulations is non-negotiable when planning to build an ADU. Zoning laws dictate critical aspects such as:

• Lot size: As of 2024, there are no minimum lot size requirements for ADUs. However, lot size could impact the ADU design and size. For example, in most single-family zones, we can build up to a certain percentage of the lot size.
• Setbacks: The current setbacks (distance of the ADU from the property line) are 4 feet for the side and rear yard.
• Height and size restrictions: Knowing the limits on how tall and large my ADU can be helps avoid planning an oversized structure that could be rejected. Additionally, existing power lines running in the back of your property could also limit the height of the ADU. That being said, you can build a one or two-story ADU.
• Parking: Currently no parking requirements for any kind of ADU
• Owner-occupancy: No owner occupancy is required, except for a JADU.

By adhering to these zoning laws and considering the local ADU ordinances that apply to your property, you can confidently navigate the ADU permit process.

Getting Quotes and Securing Financing

Some of my clients and most property owners skip this crucial step in the ADU permit process, so I always advise any property owner who comes my way to consult ADU construction costs with general contractors! I cannot tell you the times that homeowners get sticker shock when hearing the total cost of building an ADU including:

• Cost of professional services (designers, drafters, architects, engineers, energy consultant)
• ADU Permit Cost (city plan review and permit fees)
• ADU Construction Cost

Permit fees for ADUs can vary greatly depending on location and project details. They cover the costs of reviewing the plans and ensuring compliance with local zoning and building codes. There might be impact fee costs as well, like any school district payment or utility hookup. 

You can easily spend $10,000 before even breaking ground! A good ballpark number that I like to give (as of 2024) is that you’ll spend at least $10,000 in ADU plans and permit costs. The minimum cost of plans that I’ve seen is $5,000.

In my personal experience, the minimum plan review and permit cost for a garage conversion to ADU is $3,000. The larger the project, the larger the fee.

As for construction pricing, I’ve surveyed some contractors and most of them are charging a starting fee of $300 per square foot of construction. For example, if you’re building a 400-square-foot ADU, then the price of construction is $120,000. This price often excludes finishes such as cabinetry, flooring, windows and doors, and any site work and utilities trenching.

Financing Options

Here is a list of financing options you can explore to make this ADU a reality:

1. Apply for a construction loan: Seek out financial institutions that offer construction loans specifically for building an Accessory Dwelling Unit (ADU). These loans can provide the funds to cover the construction costs. Some companies offer an all-in-one package of loans, plans, and construction.
2. Home equity line of credit (HELOC): If you have sufficient equity in your primary home, you may be able to secure a HELOC to finance the ADU construction. This allows you to borrow against the value of your home and use the funds for the ADU project. This is the preferred route for most clients.
3. Personal savings or investments: Consider using personal savings or investments to finance the construction of the ADU. This can help avoid taking on additional debt and interest payments. 
4. Joint venture or partnership: Partner with an investor or developer who is interested in the ADU project. This can provide additional capital and expertise while sharing the risks and rewards of the construction. This is great if you own a rental property you want to add a second unit (via an ADU).
5. Government grants or subsidies: Research local, state, or federal programs that offer grants or subsidies for ADU construction. Check out the California Department of Housing, the CalHFA ADU Grant Program, and the Don’t Move, Improve Program by the Neighborhood Housing Services of LA County program (a local ADU program).
6. Home improvement loan: Some lenders offer home improvement loans that can be used for ADU construction. These loans may have favorable terms and can be specifically tailored to renovation and construction projects.

Remember to consult with financial advisors or lenders to explore the best financing options based on your circumstances and goals.

Creating the Architectural Drawings and the Permit Set

The next step in the permit process for your ADU is to get a design professional to draw the permit set. This design professional can be a drafter, designer, architect, or engineer. Some contractors even have their in-house architect/designer (called Design-Build Construction Company). They are the experts at understanding the zoning code applicable to your property, coming up with an appropriate layout and construction details, and navigating the building code and approval process. 

These design professionals offer a range of services, including project management, interior design, project expediting, etc. At a minimum, they should provide you with architectural drawings, structural drawings, and a Title 24 (energy report).

The process at our design company looks like this:

1. We meet with the client to talk about goals and expectations for the project
2. Do our zoning research and take measurements of everything on-site
3. Produce a layout, including a site plan, floor plans, and elevations for client review and approval. We then receive feedback from the client until the final design is approved
4. Produce the permit set (doubles as the construction plans) which includes full architectural, structural, and energy report drawings for the city permit

To read more about our Services, we encourage you to visit our Services Page.

Pricing and Timeline

Pricing (and design time frame) can vary depending on who you hire and what their role in your ADU process is. Please note that plan review and permit fees are separate from the designer’s fee. Some clients hire the designer to produce only the drawings and the homeowner goes to the city themselves to get the plans submitted and approved. Most of the time, the design team prepares the drawings and is also the permit applicant, so they submit the plans to the city for review and approval. 

We encourage everybody to go this route so it’s a hands-off process for you. However, I’ve heard countless horror stories of designers bailing on the project and running away with their client’s money. Always vet who you’re working with. The best way to find these design professionals is through referrals. 

Submitting the Plans to the City

The final step in the ADU permit process is to submit plans and a building permit application to the city. 

Some smaller local jurisdictions might require you to submit plans separately to different departments. The most common city departments that review plans are Building, Planning/Zoning, Public Works (for any improvements on the street), and Fire Department (for fire truck access and any fire sprinklers requirements).

I double-check the requirements with my local building department to ensure my submission is in line with their guidelines. Staying organized and attentive to detail significantly streamlines the permit approval process. The role of the zoning/planning department is to ensure that plans comply with the zoning code. They look at things like size, setbacks, and heights. The role of the building department is to ensure the plans comply with all applicable building codes and safety standards.

Handling Revisions and Approvals

The initial review by city staff takes anywhere from 10 business days to a month, sometimes even more if they are backed up with projects. It’s not unusual for the initial design to require revisions. The review process often involves going back and forth with the designer or homeowner to make necessary changes.

• Common Revisions include:
  • Structural modifications or clarifications
  • Changes to window sizing or placement for egress purposes
  • Clarifications on the plans, etc.

It can take anywhere from 5 business days to 2 weeks to review revisions. Meanwhile, you can get approvals from other applicable city departments. Your plans should be approved after one, or a few rounds of revisions and corrections.

Permit Issuance

Congratulations! You made it this far! This step concludes the ADU permit process.

This involves the homeowner or the contractor signing for the permit (taking responsibility for it) and paying all the permit fees, including the mechanical, plumbing, and electrical permits. These permits allow you to start building your ADU.

There you have it, the easy steps to permit your ADU.

If you have any questions, please leave me a comment or send me a message. I read and respond to every email.

And if you need help with your ADU, reach out to us. We’d be happy to assist you.

Frequently Asked Questions

How long does it take to get an ADU permit?
It can take anywhere from 3 months to 6 months, depending on how quickly you arrive at a design and how busy your city’s building department is.

How much do ADU permits cost?
I touched upon it in the Financing section of this post. Usually, they cost about 1%-2% of the building valuation you assign in the ADU permit application. For example, if you claim the ADU is going to cost $100,000 to build, then the permit cost might be $1,000 – $1,500.

Keep in mind that the permit cost is the final fee you pay after the plans are approved. This doesn’t account for any plan review fees, impact fees, or fees paid to other departments involved. This permit fee covers the cost of building inspections by the city.

How long does it take to build an ADU?
This also varies from builder to builder, and from project scope and finishes. It can be anywhere from 4 months to 15 months. The larger the ADU, the longer it is to build.

If you’re using high-end materials, like tile imported from Italy or windows with a long lead time, then it will take longer. The good thing is that ADU approvals last 6 months to a year. Building permits usually are good for 6 months to a year. The ADU permit is extended another six months every time you have a building inspection.