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New CA ADU Laws and their Implications

Since the first slate of state laws aimed at easing restrictions on ADUs passed back in 2016, the popularity of ADUs and the pace of their construction have skyrocketed. The acronym itself has gone from an obscure planning term to common parlance, and you can hardly drive anywhere in the city without coming across a billboard advertising ADU consultation or design services. In 2016, only 80 permits were issued for ADUs in Los Angeles. By 2021, that annual figure had risen to 5,064, and the rate continues to rise year after year. It is one of those rare occasions where legislation aimed at addressing a problem has worked exceedingly well, providing a successful and popular solution. Still, there have been many jurisdictions that have worked hard to find ways around the intent of these laws, spurring more bills to address these subversions. The last big round of ADU changes came in 2020. This year, we have two new bills on the subject. 

We’ll end our review of the year’s new housing laws by discussing these new ADU laws and their implications. Passed nearly unanimously by state lawmakers, AB 2221 and SB 897 work together to further restrict local regulation of ADUs. In essence, what these laws aim to achieve is a more permissive, state-mandated local ADU program. And while there is much to be excited about for all ADU prospects, I’ll focus mostly on what these laws mean to multifamily (MF) ADU projects.

The two laws are complementary, and they work to clarify the language and intent of previous ADU laws as well as provide for (slightly) more permissive development standards. Regarding the former, the language ambiguities addressed were how more restrictive jurisdictions took solace in continuing to restrict ADUs, so having the clarifications codified in new laws goes a long way toward alleviating municipal NIMBYism.

ADUs allowed with proposed projects as well as existing

One big (huge?) win that comes from this language change for MF developers is the inclusion of the word "proposed" when addressing how many detached ADUs need to be allowed on a project. Previous versions of the ADU laws have allowed for up to two detached ADUs to be allowed for multifamily projects, but only existing MF projects were explicitly addressed in the letter of the law. This led to ridiculous situations in which new MF projects were allowed the extra units, but the permitting and construction of them could not start until the main MF structures were built and had received their certificate of occupancy. I faced this situation myself on many projects, and for obvious reasons, it was all but assured that the additional ADU units would be abandoned. The logistical and financial challenges of having to mobilize construction crews multiple times for the same project and the fact that the completed MF would have to sit at least partially empty to allow for the subsequent construction of the ADUs meant that these additional units were not feasible. Thankfully, this is now a problem of the past, as the new laws clarify that applications for up to two detached ADUs shall be allowed with both proposed and existing MF projects.

Regarding the allowance for units within MF projects, however, the new laws make little change to existing regulations. At least one ADU and up to 25% of the existing MF units are allowed within existing portions of the MF structures that are non-livable spaces such as storage rooms, boiler rooms, passageways, attics, basements, or garages. These are still only allowed in existing MF projects, not proposed ones.


Another major(ish) change coming from the new laws regards allowable heights of ADUs. The baseline is still 16’ for most detached ADUs, but this number is slightly increased for certain situations. A minimum height of 18’ is now allowed for any project that is within a half-mile walking distance of public transit or any project on a lot with a proposed or existing MF, multistory building. Now, this increase is great and all, but it continues to be a somewhat frustrating number. Realistically, an 18-foot height limit still means only a one-story building unless the ground floor is excavated below grade to some degree. There is an allowance for an extra 2’ in height to match the roof pitch of the main buildings, but this is for existing projects only.

For attached ADUs, the minimum height limit is now stated as 25’ or the underlying zoning height limit, whichever is less. This is a benefit mostly to projects working on lots with single family homes,since attached ADUs don’t seem to be mentioned in the new laws in regards to MF projects. However, they are not specifically disallowed for MF projects either so there could be a feasible path forward to requesting one attached ADU and one detached ADU on a MF project: one would be capped at 25’ and the other at 18’. This is vague territory, though, and such an approach would depend on how each municipality codifies these rule changes in their own ordinance. As of the writing of this post, L.A. has yet to release a new ordinance reflecting the new laws.

Approval time and R Occupancy

The time that a local jurisdiction has to act on an ADU application is now set by law at 60 days. Previous versions of AB 2221 explicitly included in this approval/review process any input from interdepartmental organizations, but that has been removed from the final version of the bill. This matters because oftentimes the longest wait times for ADU approvals come not from LADBS but from other reviewing agencies such as LADWP. Again, we’ll have to see how this is handled as the new ordinances take shape.

The 60-day limit can be prolonged or postponed for ADU applications that are submitted alongside an application for a proposed new main dwelling project. In these cases, the review period for ADU applications begins after a decision has been made on the new main structures, be they SF or MF.

Another potentially game-changing aspect gets into the weeds of the building code a bit: it is the disallowance of a change in R occupancy because of the addition of an ADU. For MF developers, this potentially means a duplex-plus-ADU proposal would be reviewed under the CA Residential Code instead of the CA Building Code. The biggest benefit of this would be not having to adhere to accessibility standards. Again, however, the state language is broad and a bit vague, so it will be a wait-and-see approach on this until L.A. codifies a new ordinance.

All in all, ADU legislation—along with most other housing legislation—continues to take a more permissive approach with this year’s housing laws. If I may say so humbly, it is a step in the right direction, as these ADU allowances have made for the most dependable avenue to add density without a mountain of red tape. The manner in which local municipalities adopt these laws via ordinance will still matter, however, as there are always loopholes to be had or idiosyncrasies to look out for. So, as always, if you’re planning on adding ADUs to your own development project, make sure you work with someone who is familiar with the process and rules. If you have questions about what I’ve highlighted here, please reach out for a quick discussion. These laws provide a way to combat stringent zoning and provide real results in terms of density. Still, with a housing deficit of over a million units in California, there is still more to be done to facilitate building more housing. More on that soon.