ADU Permits: The Ultimate Guide on Everything You Need to Know

May 23, 2022

Accessory dwelling units (ADUs) are becoming increasingly prevalent in California, and that’s partially thanks to recent state legislation. This legislation eliminates the planning process for certain ADUs – but ADU permits are always necessary. 

On top of all these costs come the paperwork and the actual work of surveying your site, lining up contractors, and more. It’s a lot – especially without a turnkey ADU services provider handling it for you – but the below ADU permits guide can help. Whether you’re interested in detached ADUs behind your single-family dwelling or interior conversions in your basement or garage, this guide can point you in the right direction.

What you need to know about ADU permits

As you pursue ADU permits, you should keep the below five considerations in mind.

1. ADUs require certain included rooms and amenities.

An ADU is an accessible dwelling unit, so it must come with everything a full-sized house would include. Your ADU must include a living area and a sleeping area – these can be combined as with a studio, or separate as with a one-bedroom. There must be a bathroom with a working toilet, shower, and sink, and there must be a kitchen as well. A separate entryway that occupants can access without entering the primary dwelling is also necessary.

All ADU kitchens must meet additional requirements. Your ADU’s kitchen must include cabinets, a countertop, a functioning sink, and an eating area. You cannot substitute a microwave, toaster oven, or hot plate for a stove. 

2. Your city may have unique design and permitting restrictions.

It’s entirely possible that your city may enforce certain restrictions upon how you design your ADU. It’s also realistic for your city to require additional permits beyond what you need at the state and county levels. Usually, you can easily stay within the boundaries of all these restrictions – and that’s even easier to achieve with Spacial at your side. At Spacial, we can design your ADU to fit local regulations and work with the proper bodies to ensure your project is in compliance. 

3. Your ADU must adhere to your HOA's rules.

California Assembly Bill (AB) 670 invalidates any HOA rule that “unreasonably restricts the construction or use” of an ADU on a single-family residence lot. However, the key phrase here is “unreasonably restricts” – HOAs can still enforce “reasonable” rules on your ADU. For example, if you’re subject to HOA rules, the association can still demand that your ADU fall in line with the community’s architectural style.

4. You can skip the planning stage if your ADU meets certain requirements.

Employee organizing a projects workflow
Photo by Alvaro Reyes on Unsplash

In 2020, California passed legislation that automatically exempts certain ADUs from the planning stage. In other words, you can build an ADU without California state, city, or county permission if it meets all these criteria. According to these laws, an ADU of less than 800 square feet can skip planning. The ADU must also include four-foot rear and side setbacks and be less than 16 feet tall. Otherwise, planning may still be required. 

What you need to apply for permitting and approval

All permit applicants should bring the following documents to the table.

  • A list of licensed contractors. Who will work on your project if it’s approved? Zoning and planning boards need to know the answer before they can issue your permits. Presenting a list of licensed contractors is the best way to give planning boards what they need here. When you choose a turnkey ADU services provider like Spacial, you’ll know exactly who’s doing what – and Spacial will prepare your contractor list.
  • ADU permit plan set. You’ll need to present a permit plan set for your ADU project to get it approved. This plan set will tell your local regulatory bodies exactly what’s happening inside your ADU. It’s a big part of what they need to approve your permit application.
  • Engineering surveys (potentially). You may need to present the results of your engineering surveys before applying for your ADU permit. When you choose Spacial, we’ll conduct these surveys and prepare your ADU plan set. We’ll also handle all the steps before, during, and after you apply for your permits, including responding to city comments. 

The most commonly required ADU permits

To build an ADU, you’ll need the below permits.

1. Building permit

You must obtain a building permit to begin an ADU project unless California’s 2020 state law exempts you from the planning stage. These permits show that you’ve met your local jurisdiction’s requirements for building an ADU. These restrictions can include your unit’s height, square footage, and more. 

Applying for a building permit requires the creation of a permit set comprising several ADU plans drawn to scale. Your permit set will detail your ADU to your regulatory authorities so they can easily see whether you’re meeting local zoning codes. It will also give them a quick reference for requesting changes. A turnkey ADU services provider such as Spacial can create your permit set and obtain your permits on your behalf.

2. Electrical, plumbing, and mechanical permits

Person using a volt meter
Photo by Shirish Suwal on Unsplash

Part of the ADU building process is preparing your site’s utilities and connecting your unit to these utilities. As a result, you may need to obtain electrical and plumbing permits. You may need to seek these permits from your city government or utility providers. But you don’t have to figure that out yourself. Spacial can look into all your required permits – and how to get them – on your behalf.

3. Location permits

California’s Coastal Act oversees all development along the state’s coast. It supersedes local laws as well, meaning that even if your coastal ADU can skip the planning process, it must obtain a coastal development permit. This permit is one of two types of location permits that your ADU could require.

You may also require a geologic hazard clearance if your site lies within a designated landslide or geohazard zone. San Jose, for example, names the geologic hazard clearance as potentially necessary in its ADU universal checklist. At Spacial, our years of experience building in San Jose, Santa Clara County, and all of the Bay Area ensure you’ll get this permit. 

Tips for obtaining your ADU permits

Whether your ADU will be the state average of 615 square feet or a 400-square-foot studio, the below tips can make the permit process easier.

1. Apply for the CalHFA ADU Grant Program

The California Housing Finance Agency (CalHFA) offers certain homeowners grants of up to $40,000 to build an ADU. These grants can lower the cost of your permits. They have, to date, helped finance 2,500 ADUs.

You can apply for grant funding if you also apply for construction loans from a lender that’s part of the CalHFA ADU Grant Program. If you’re approved for a loan and your income is low or moderate according to CalHFA standards, you’ll prequalify for a grant. 

You can then apply for the grant as your ADU partner prepares your site to receive your unit. You’ll need to include all site preparation invoices and costs alongside your application. Thereafter, if CalHFA approves your application, it will send you grant money to help cover your ADU costs. 

2. Speak with other California homeowners who have built ADUs

According to the UC Berkeley Center for Community Innovation, the number of California ADU permits issued in 2020 was nearly 3,400 greater than in 2018. That means you’re increasingly likely to know another California homeowner who has built an ADU on their property. You can turn to these homeowners for advice: What did they learn along the way? What did they wish they knew beforehand? How much did they end up spending? But keep in mind that other homeowners aren’t experts, so your experience may differ.

3. Work with turnkey ADU service providers that handle permitting for you

Obtaining ADU permits can be confusing – and building an ADU can be just as challenging. That fog can clear when you hire a turnkey ADU service provider to handle the entire process from start to finish. Spacial is a great example.

At Spacial, we’ll start with a site visit and survey to get a sense of what you’ll need to build your ADU. We’ll then create your permit sets and get your ADU permits from the right government agencies. That’s especially easy for us – we offer studio and one-bedroom ADUs, always with the same floor plans. We know how to get these ADUs government-approved because we’ve done so time and again.

Once we’re good to go, we’ll start preparing your site and foundation. At the same time, we’ll assemble your volumetric modular unit offsite. That means once we’ve connected your utilities and installed your foundation, we’ll crane your ADU into place in one piece. Your ADU will arrive ready to go, and we’ll add furniture through our West Elm partnership. We’ll then present you with your final occupancy permits and hand you the keys. That’s all it takes to enjoy more space – and more life.

Contact Spacial to breeze through the ADU permit process

Kitchen in Spacials Studio ADU
Photo by Spacial

Obtaining ADU permits doesn’t have to be an uphill battle – especially with Spacial in your court. Contact us today to discuss your ADU vision and learn how hands-off you can be with the permitting process. Just four to nine months after you officially get started with us, you’ll walk into a fully permitted ADU you’ll absolutely love.