An SGV Apartment Building Can Now Add Up to 8 Detached ADUs, Not 2

What changed

If you own an apartment building or any lot with more than one existing home on it, you can now add more backyard units than before. A state law called SB 1211 raised the cap on detached ADUs at a multifamily property from 2 to as many as 8. It took effect January 1, 2025.

An ADU (accessory dwelling unit) is a second, smaller home on the same lot as an existing one. "Detached" means it's a separate structure, not an addition to the main building. Before SB 1211, state law let a multifamily property add up to 2 detached ADUs, no matter how many units the property already had. Now it can add up to 8, as long as the new units don't exceed the number of homes already on the lot. A duplex can add up to 2, the same as before. A 6-unit apartment building can add up to 6 detached ADUs. A 10-unit building can add up to 8, the cap's own ceiling. This higher cap only applies to a lot with an existing multifamily building on it. A brand-new multifamily project that hasn't been built yet still follows the old rule and is capped at 2 detached ADUs.

Who this applies to

SB 1211 only changes the rule for lots that already have multifamily housing on them, such as an apartment building or a duplex. It does not touch the separate rule for a lot with one single-family home. A different law, AB 956, covers that. Own a single-family lot with one house on it? This law isn't the one that applies to you.

The rules that come with the extra units

SB 1211 amends Gov. Code §§ 66313, 66314, and 66323, the state's base ADU statute. The added units still have to follow the state's standard ADU limits:

• A detached ADU can be up to 1,200 square feet.
• Height is typically 16 to 18 feet (Gov. Code § 66321).
• Side and rear setbacks, the required distance from the property line, can be no more than 4 feet.
• Cities must give ministerial approval within 60 days. Ministerial means staff checks the plans against written rules and must approve them if the plans meet those rules. There is no hearing and no discretionary review.

SB 1211 adds two things on top of those standard limits. First, a city can no longer require you to replace parking spaces you demolish or convert to build the ADUs, even uncovered ones. You can turn a surface parking lot or a carport into housing without adding parking back. Second, the law defines "livable space" for the first time, which affects how a city measures the unit's size limits.

How it affects each side

For an owner of a multifamily property, this is a straightforward way to add rental income. A 6-unit building with room in the back could realistically go to 12 units, approved by staff, with no hearing to attend and no parking to rebuild. That changes what the property is worth and what it can earn.

For tenants already living on the property, more units on the same lot can mean more competition for existing parking and shared outdoor space, since the law removes any requirement to replace what's converted. For neighbors, there's no public hearing to attend or oppose. The ministerial process that makes this fast for owners also removes the usual chance for a neighbor to weigh in before it's approved.

What this doesn't change

SB 1211 has no direct tax effect. It doesn't change the single-family ADU rules (AB 956 does that separately), and it doesn't touch impact fees, which a different law, SB 1117, covers. It also doesn't override a city's own objective design standards, as long as those standards don't conflict with the state minimums above.

Who to contact

• Your city's building or planning department (owners and builders): processes the ministerial ADU permit itself, including plan review, the 60-day clock, and any local design standards that don't conflict with the state minimums above. Contact information is on your city's own website.
• California Department of Housing and Community Development (HCD), Housing Accountability Unit (anyone): reviews reports that a city's ADU ordinance or permit practice conflicts with state ADU law, including SB 1211's detached-unit cap. Email: HAUPortal@hcd.ca.gov. Website: hcd.ca.gov/hau/portal.

Before you act

This article is general information, not legal advice. Laws change, and every property is different. Before you act, talk to a licensed California real estate attorney. For tax questions, also talk to a CPA.