11 California ADU Rules and Regulations to Know
The state of California passed a series laws and regulations in 2020 that have made it easier than ever to add an Accessory Dwelling Unit (ADU) to your property. If you are in the market for an “ADU-able property,” here are the 11 statewide ADU laws that you should know about if you are considering building an ADU.
- No more owner-occupancy
This is one of the biggest changes in the law that have helped make it easier for homeowners to build ADUs. As of 2020, anyone who builds an ADU on their property will not be subject to owner-occupancy requirements for the next five years. The best part? If you build an ADU within the next five years, you are grandfathered into having any owner-occupancy requirements waived. This means that you, as the homeowner, are not required to live on your property – giving you the freedom to rent out both your primary home and ADU to generate maximum income potential.

- Increases minimum ADU size
Although in 2017, the state mandated that ADUs can not exceed a maximum of 1,200 sq ft., local jurisdictions were still able to enforce strict size requirements throughout the state. Now, the state has clarified that cities must allow ADUs with a minimum of 800 sq ft or 1,000 sq ft for an ADU with one or more bedrooms.
- Reduces application review time to 60 days
Applying for building permits can be one of the biggest bottlenecks to hold back any ADU project. This is why the state of California has mandated that city building departments must act on any ADU application within 60 days. Now, this doesn’t mean that you will have approved building permits in hand within 60 days. It means that local jurisdictions must act within a specified time window that has been greatly reduced from the original 120 day requirement.
- HOAs must allow ADUs
Conditions, Covenants and Restrictions (CC&R’s) define the rules of home ownership within Homeowners Associations (HOAs). Previously, CC&R’s could limit a homeowner’s ability to add an ADU to their property. As of 2020, CC&R’s and HOAs can no longer prohibit the creation of an ADU on single-family properties. That being said, it’s important to know HOAs still have the ability to impose their own restrictions. Make sure to check with your HOA association’s rules on ADUs.

- Parking exemptions for garage conversions
Garage conversions are one of the easiest and most popular ways to add an ADU to a property. However, in the past, homeowners had to find replacement parking somewhere on their property. This was a challenge because if you didn’t have space on your property to add these parking spots, you were unable to build an ADU. Now, if you convert your garage in to an ADU, you are not required to replace the parking spots taken away by the ADU on your property.
- More parking exemptions!
ADUs must have at least one parking spot on the property. However, if your property is located within a ½ mile walking distance from public transit, a parking spot is not required for the ADU. Additionally, you will not need to provide parking for the ADU if:
- The property is located within a historically significant district
- The property is located within a block of a car share vehicle
- The ADU is attached to the primary dwelling
- Waives DIF Fees for units under 750 sq ft.
Development Impact Fees (DIF) can be one of the most costly expenses when building an ADU, and can cost up to tens of thousands of dollars. Ready for the good news? As of 2020, the state has waived all DIF fees for ADUs below 750 sq ft. For units over 750 sq ft, DIF fees will be assessed in proportion to the size of the primary dwelling on the property.
Luckily, here in San Diego, both the city and county have waived DIF fees for all ADUs – regardless of size.

- Minimizes setback requirements
Strict setback requirements can make it challenging, and sometimes impossible, to build an ADU.
What’s a setback?
It’s essentially the minimum distance away from a property line that a structure can be built. Assembly Bill 68 has made things easier by allowing setbacks of no more than 4 feet from the side and rear property lines for the construction of an ADU.
- Allows both an ADU and JADU on the same lot
This new law change creates the potential to turn a single family home into a 3-unit property. JADUs are a lower-cost way to add a rentable unit to your property, however it is important to note that JADUs require owner occupancy. ADUs on the other hand, do not require owner occupancy if built within the next five years.
- Solar exemptions for certain ADUs
As of 2020, all new construction in the state of California must be powered by solar. However, garage conversions or attached ADUs are exempt from this requirement. What does this mean? Yes, more savings on the cost of building your ADU!
- No minimum lot size requirements
In the past, cities that weren’t friendly towards ADUs would impose strict minimum lot size requirements. For example, certain cities would require extremely large lot sizes in order to be eligible for an ADU. Now, there are zero minimum lot size requirements throughout the state. Any single-family zoned property and certain multifamily properties are allowed to have an ADU.
City of San Diego and County ADU Regulations
These state laws provide the minimum that local jurisdictions must allow for ADUs. The City of San Diego and County of San Diego have provided their own ADU regulations to provide additional guidance for homeowners and potential homeowners throughout San Diego.
Ready to have your own ADU?
If you’re a first-time buyer looking to buy a home with maximum ADU potential or investor looking for your next investment property, look no further.
As San Diego’s ADU Agent, I can help you locate the best properties with maximum ADU potential currently available on the market. With my ADU expertise, I can help identify characteristics that make a particular property ideal for ADUs, as well as point out any red flags that may make things more challenging.
As an ADU consultant, I’ve helped many homeowners navigate the ins and outs of ADUs. With local laws and regulations constantly evolving, it’s important to work with a knowledgeable professional. If you’re searching for a property with maximum ADU potential, contact me today!
Resource:
Department of Housing and Community Development
Disclaimer:
The information presented in this article is based off of publicly available information at the time of writing. These claims are not guaranteed. Since ADU laws are constantly evolving, it is the homeowner’s or prospective homeowner’s responsibility to conduct due diligence in understanding the current ADU laws and regulations affecting their local municipality. To learn more, see our disclaimer.