To help solve its housing crisis, California has recently made changes to its state laws to make it easier and cheaper to build ADUs. The new laws are numerous and confusing, so in this post I will summarize them in a chronological fashion so you can see all the important changes in one post. For each new law I will provide you with the official law link and a brief summary of what the important changes are. I will also have some commentaries (in italic) regarding the laws that were effective in 2017 and how they helped me build my ADU. Keep in mind that recent laws have made it even easier and cheaper now to build an ADU then when I built mine!
Effective January 1, 2017
- Establishes “Accessory Dwelling Unit (ADU),” essentially making it easier for homeowners to convert an existing garage into a living space by easing local requirements.
- Prohibits counties and cities from requiring ADUs to have fire sprinklers when they are not required for the main residence. I knew of people who never bothered to convert their garage into an ADU because of previous fire sprinkler requirements. This law essentially guaranteed that most ADUs will not need to have fire sprinklers. When I submitted my ADU drawings to the County for review, the drawings were also passed along to the Fire District for review. The Fire District approved my ADU without requiring fire sprinklers because I never had fire sprinklers in my main house.
- Prohibits counties and cities from considering the accessory dwelling units to be a new residential for purposes of calculating the cost of utility, water, and sewer. This law change drastically lowered the cost and sped up the approval process for an ADU. For my project, I did not have to install a new water meter or power meter, which would have cost in the upward of tens of thousands of dollars. However, I did have to pay a “capacity fee” to the sewer district but it was only a few thousands. The permit clerk at the sewer district even told me that if I had done my project the year before, it would have cost me three times as much to get permit and approval from the sewer district.
- Provides more clarity for attached and detached ADUs.
- Prohibits setback requirements for an existing garage that is converted to an ADU. This was a very important exemption for my ADU project because my existing garage only has a 3 feet setback to the fence line, which is less than the 5 feet typical setback. Getting a variance for this requirement would have been difficult because I would need to ask for consents from my neighbors. Alternatively, I would have had to knock down the existing garage and build a brand new ADU with the 5 feet setback, which would have been a lot more expensive. This law definitely made my project possible.
- Parking requirements for ADUs shall not exceed one parking space per unit or per bedroom. These spaces may be provided as tandem parking on an existing driveway. No additional parking is needed if the ADU is located within 1/2 mile of public transit. I did not having have a parking problem for my project because my driveway can accommodate up to four cars and there’s a bus stop five houses down from where I live. However, this is an important exemption to know especially for locations with minimal space for additional parking.
- Allows local governments to adopt an ordinance permitting junior-ADUs. JADUs are ADUs that do not exceed 500 square feet and are completely contained within an existing residential structure. This law doesn’t apply to my project because my ADU is detached and it is larger than 500 square feet. However, it’s good to know more about JADUs because they have certain advantages to an regular ADU (no parking requirements, less building permit fees, etc…). I would suggest that you look into JADUs if you are only looking to convert an existing bedroom inside your house into a separate living unit with a separate entrance, restroom, and kitchen.
Effective January 1, 2018
- Clarifies that an ADU can be created through the conversion of a garage, carport or covered parking structure.
- Requires special districts and water companies to charge a proportional fee scale based upon the ADUs size or its number of plumbing fixtures.
- Reduces the maximum number of parking spaces for an ADU to one space.
Effective January 1, 2019
- Homeowners who previously created accessory dwelling units (ADUs) without the required building permits may have the opportunity to bring their ADUs into compliance. For ADUs that were constructed without building permits, local building officials now have the option to inspect the existing ADU and apply the building standards that were in effect at the time the unit was constructed to provide an official permit to the previously unpermitted ADU.
Effective January 1, 2020
- Prohibits local agencies from adopting ADU ordinances that impose minimum lot size requirements.
- Prohibits the application of lot coverage, floor area ratio, or open space regulations that would prevent an 800 square foot ADU.
- Prohibits replacement parking requirements when an existing garage is converted to an ADU.
- Limits local discretion in establishing minimum and maximum unit size requirements, guaranteeing at least an 850 square foot unit ADU, or 1000 square feet for an ADU with more than one bedroom.
- Caps setback requirements to 4 feet.
- Two ADUs are now allowed on a single-family home lot: one ADU (attached or detached) and one junior ADU (contained within the existing house).
- Multiple ADUs are allowed within an existing multi-family building or up to two detached ADUs on a lot with an existing multi-family building.
- Until Jan 2025, cities may not condition the approval of ADU building permit application on the applicant being the “owner-applicant” of either primary dwelling or the ADU.
- The agencies cannot impose impact fees on ADUs under 750 square feet. Any impact fees assessed for larger ADUs must be proportional to the square footage of the primary residence. This law is a game changer. When I applied for the permit for my ADU, I was required to pay a “traffic impact fee” of close to $8,000 by the County. This “traffic impact fee” was the same at $8,000 whether I’m building an ADU, a brand new house, or a 4-unit apartment! The new law reduces the “traffic impact fee” for new permit applicant to $0 if your ADU is less than 750 square feet!
- Local agencies may now allow ADUs to be sold or conveyed separately from the primary residence if certain conditions are met.
- Prevents homeowners’ association from banning or unreasonably restrict the construction of ADUs on single-family residential lots.
Effective January 1, 2022
- Passed in September 2021, this controversial law goes far beyond ADU and could lead up to 4 dwelling units on parcels where currently only one exists. It does this by allowing single-family parcels to be subdivided into two lots and allowing a new two-unit building to be constructed on each of the newly formed lot. There are some restrictions such as each new parcel needs to be at least 1,200 square feet, but this law will make it much easier to split lots and building of denser housing.
This post is not meant to be the official interpretation of the California laws or an exhaustive list of all California ADU laws, but rather what I think are the important California ADU laws and my own personal understanding of what the laws said. I suggest you go read up on the specific laws yourself (link provided) or consult with an attorney if needed before making decisions based on the California ADU laws.
If you are looking to get in touch with a Contractor to help you with your ADU project, reach out to me at [email protected] and I can give you recommendations for some excellent Contractors.