We are moving into an exciting new era of ADU development with the passage of AB 1332. This legislation requires permitting departments to pre-approve plans submitted by architects and designers that are not site specific. In other words, it is only the building itself that will be approved, but there are still site-specific parts of the plan that must be prepared when submitting for a permit on a pre-approved plan.
Pre-approved plans provide detached, site-built ADUs that must be constructed precisely as outlined in the designs, without any modifications to retain their pre-approved status. If you’re fortunate enough to discover the ideal plan for your property, don’t hesitate to contact the designer listed in the posting; you may even find that some plans are available at no cost!
While the building itself won’t require further review, you will need engineering plans for the foundation and a site plan detailing utility connection, drainage solutions, and other necessary site work. These additional permitting documents can be coordinated by the designer or homeowners can collaborate with a general contractor to assemble a team capable of creating these plans and submitting them for approval.
Pre-approved plans also include both state and federally approved prefabricated ADUs. Like pre-approved site-built plans there is no customization allowed if you wish to maintain the pre-approval, and foundation, utility, and sitework plans will need to be created and submitted for permit. With pre-approved prefabs you don’t need to worry about the dual permitting track at the local and state or federal level. In this case you will reach out to the manufacturer to pay for the plans, and they can help you facilitate the sitework approval, or you can work with a general contractor who will do the site work to coordinate the professional team and submit plans to the local jurisdiction. We also recommend checking with your insurer and financing institution before going down this path.
Under the new state law, permitting departments have 30-days to either approve or deny a permit application for a pre-approved plan.
You may also be learning or hearing about Pre-designed plans. These are popular ADU plans for detached site-build ADUs that designers and architects may make available to help you get inspired. Pre-designed plans are customizable, so you will work with the designer to tweak the layout so that it meets your specific needs and desires. This can include changing the size and/or placement of windows and doors, matching exterior finishes to your existing home, etc. Like pre-approved plans, pre-designed plans save both time and money as much of the layout has been completed. When working with a pre-designed plan, you will work with the designer to coordinate the professional team for engineering, utility and site work and a complete permit set of plans will be submitted for approval. Some jurisdictions display pre-designed plans on their website. However, these plans are not pre-approved by the jurisdiction, and they are not subject to the 30-day review period.
You can also always look through this smorgasbord of ADU plans and find aspects of many designs that you like and a designer whose styles you love and reach out them to get pricing on a custom design for your very own ADU. But remember, in all cases you must make sure that the design meets the constraints of your budget, site, and the requirements under the current Title 24 California Building Standards Code, which is subject to change again in 2025, taking effect January 1, 2026. That means all pre-approved plans will need to be resubmit for approval prior to that date or you will want to get your project submitted prior to that date to be evaluated under the previous code cycle.
We wish you the very best of luck in all your housing endeavors and know that we are here to help if you need us.
Cheers!
Hello Housing and the Hello ADU Team