California’s ADU laws in 2026 let most single-family lots add a detached ADU, an ADU inside or attached to the house and a junior ADU, with no owner-occupancy rule for the ADU, 4-foot setbacks, and a 60-day approval clock. Two new 2026 laws tighten that clock and loosen junior ADU rules. And on January 1, 2027, AB 956 and SB 1117 add a second detached ADU and cut impact fees on bigger units.
If you’re buying an investment property to add an ADU in Orange County or LA County, this is the one page that pulls every current rule together. I link to my deeper write-ups on each law along the way.
California ADU Laws at a Glance
| Law | What it does | In effect |
|---|---|---|
| AB 68 / SB 13 (2019) | Created today’s framework: 60-day approval, 4-ft setbacks, ADU + JADU on one lot | Jan 1, 2020 |
| AB 2221 (2022) | Height minimums (16, 18 and 25 ft), denial must list every deficiency | Jan 1, 2023 |
| AB 976 (2023) | Permanently bans owner-occupancy requirements on ADUs | Jan 1, 2024 |
| AB 1033 (2023) | Lets cities opt in to selling an ADU separately as a condo | Jan 1, 2024 |
| SB 477 (2024) | Moved ADU law to Gov. Code §§ 66310–66342 (no rule changes) | Jan 1, 2025 |
| AB 2533 (2024) | Easier legalization of unpermitted ADUs built before 2020 | Jan 1, 2025 |
| SB 1211 (2024) | Up to 8 detached ADUs on existing multifamily lots | Jan 1, 2025 |
| SB 543 (2025) | 15-business-day completeness review, appeals, school-fee exemption under 500 sq ft | Jan 1, 2026 |
| AB 1154 (2025) | No owner-occupancy for JADUs with their own bathroom; JADU rentals must be 30+ days | Jan 1, 2026 |
| AB 462 (2025) | ADU can get a certificate of occupancy before a fire-destroyed main home; 60-day coastal permits | Oct 2025 / Jan 2026 |
| AB 956 (2026) | Two detached ADUs on a single-family lot | Jan 1, 2027 |
| SB 1117 (2026) | Impact fees only on square footage above 750 | Jan 1, 2027 |
The best single reference for the statewide rules is the California HCD ADU page and handbook. Cities can be more generous than state law, but not stricter.
What You Can Build on a Single-Family Lot in 2026
In 2026, state law guarantees these options on most single-family lots:
- One ADU inside the house or an existing accessory structure, like a garage conversion, with up to 150 square feet added for access.
- One new detached ADU of at least 800 square feet, 16 feet tall, with 4-foot side and rear setbacks.
- One junior ADU (JADU) of up to 500 square feet inside the home.
Those can be combined. That’s three rentable units on many lots before you ever touch SB 9. I explain the JADU size rules in California Junior ADU Size: The 500-Square-Foot Rule.
Size and height limits
| Rule | State standard |
|---|---|
| Minimum size a city must allow | 850 sq ft (studio or 1-bed), 1,000 sq ft (2+ beds) |
| Guaranteed detached size | 800 sq ft regardless of lot coverage or FAR |
| Maximum detached size | 1,200 sq ft |
| Attached ADU | Up to 50% of the main home, but never less than the 800–1,000 sq ft floors |
| Height, detached | 16 ft; 18 ft near transit (plus 2 ft for roof pitch) |
| Height, attached | 25 ft or the zone’s limit, whichever is lower |
| Side and rear setbacks | 4 ft (none for a garage conversion or same-footprint rebuild) |
SB 543 now says those sizes are measured as interior livable space, so exterior walls don’t eat into your allowance. Setbacks are where cities still try to push back. See ADU Setback Requirements in Orange County.
Parking and owner-occupancy
- Parking: At most one space per ADU, and none within half a mile of public transit, in a historic district, or when you convert a garage. A city can’t make you replace garage parking you convert.
- Owner-occupancy: Never required for an ADU (AB 976). For a JADU, only required when it shares a bathroom with the main house (AB 1154).
- Short-term rentals: Cities can require ADU rentals to be 30+ days. AB 1154 now requires that for JADUs.
What Changed on January 1, 2026
SB 543: faster permits and lower fees
SB 543 gives cities 15 business days to tell you if your application is incomplete. Miss that, and it’s deemed complete. The 60-day approval clock then runs from there. It also:
- Creates an appeal path for incompleteness findings and denials, with a decision due within 60 business days.
- Exempts ADUs and JADUs of 500 square feet or less of interior livable space from school fees.
- Bars sprinkler requirements for a JADU when the main home doesn’t need them.
- Stops cities from delaying an ADU approval until the main home is permitted.
AB 1154: JADUs become real rentals
Before 2026, a JADU meant the owner had to live on the property. Under AB 1154, a JADU with its own bathroom no longer carries that requirement. That makes the JADU a viable add-on for a pure investment property. LA County’s planning memo on SB 543 and AB 1154 shows how one jurisdiction is applying both laws.
Laws From 2024 and 2025 Investors Still Use Every Day
- AB 2533: legalizing unpermitted units. For ADUs built before January 1, 2020, a city generally can’t deny a permit over code violations unless the unit is a health and safety hazard. This changes the math on homes with bootleg garage units. See my AB 2533 inspection checklist.
- SB 1211: multifamily lots. On a lot with an existing duplex or apartment building, you can add up to eight detached ADUs, capped at the number of existing units, plus interior conversions. I cover the counting rules in California’s Multi-Unit ADU Rule.
- AB 1033: ADU condos. Cities can opt in to letting owners sell an ADU separately. Few have so far. Here’s what California’s first ADU condo sale means.
- AB 1482 exemption. A newly built ADU is exempt from the statewide rent cap for 15 years. Details in AB 1482 and New ADUs.
What Changes on January 1, 2027
Two laws signed on September 29, 2026 take effect next January.
- AB 956: two detached ADUs. Cities must approve up to two detached ADUs on a single-family lot. If you build two, the city no longer has to also allow a JADU. HOAs also can’t block legal ADUs or JADUs. Read AB 956: Two Detached ADUs in California.
- SB 1117: no more 750-square-foot fee cliff. Impact fees apply only to the square footage above 750, not the whole unit. That makes a 1,000-square-foot 2-bedroom cheaper to permit. See SB 1117 Is Law.
- SB 1196: utility hookup deadlines. Sets deadlines for utilities to connect new ADUs, the delay most owners never budget for. My breakdown: SB 1196 and ADU Hookup Delays.
What It Means for Investors Buying in 2026
| Lot type | 2026 maximum (typical) | 2027 maximum (typical) |
|---|---|---|
| Single-family, no garage to convert | 1 detached ADU + 1 JADU | 2 detached ADUs, or 1 detached + JADU |
| Single-family with detached garage | Garage conversion ADU + detached ADU + JADU | Conversion plus up to 2 detached, depending on city rules |
| Duplex or 4-plex | Up to 2 detached ADUs + 25% of units as conversions | Same; SB 1211 allows up to 8 detached on larger buildings |
Unit counts vary by city and lot, and the 2027 rows depend on how each city updates its ordinance. The practical takeaway: buy the lot for 2027, not 2026. A 7,000-square-foot lot with alley access that holds one ADU today may hold two detached ADUs next year. That’s where I focus my buyer searches.
City Rules Still Matter
State law sets the floor, but your city runs the permit counter. A few patterns I see in Orange County and LA County:
- Cities with out-of-date ordinances have to follow state law anyway. HCD reviews local ordinances and sends letters when they conflict.
- Huntington Beach keeps fighting state housing law and losing. See Huntington Beach Keeps Losing Its Housing Law Fight.
- Unincorporated LA County amended its ordinance in 2026. See LA County’s 2026 ADU Ordinance Amendment.
- Fire zones, coastal zones and historic districts still add review steps.
Frequently Asked Questions
What are the new ADU laws in California for 2026?
SB 543 adds a 15-business-day completeness deadline, an appeal process and a school-fee exemption for units of 500 square feet or less. AB 1154 removes owner-occupancy for JADUs with their own bathroom and requires JADU rentals of 30+ days.
How many ADUs can I build on my property in California?
In 2026, typically a conversion ADU, one detached ADU and one JADU on a single-family lot. Starting January 1, 2027, AB 956 allows two detached ADUs.
Do I have to live on the property to build an ADU in California?
No. AB 976 permanently bans owner-occupancy requirements for ADUs. A JADU requires it only if it shares a bathroom with the main home.
How big can an ADU be in California?
Cities must allow at least 850 square feet for a studio or 1-bedroom and 1,000 square feet for 2+ bedrooms. Detached ADUs can go up to 1,200 square feet where the city allows it.
How long does a city have to approve an ADU?
15 business days to confirm the application is complete, then 60 days to approve or deny it.
Can I sell an ADU separately from the house?
Only in cities that opt in under AB 1033 and only as a condo. Most cities in Orange County and LA County haven’t.
Find a Lot Built for the 2027 Rules
The laws are now on the investor’s side. The hard part is finding the lot where two detached units, utilities and access all actually fit. I screen every property for that before you write an offer.
👉 Book a buyer ADU consult call to go through your options with Dylan
Prefer to talk now? Call Dylan Serna, ADU Realtor at 714-860-2868.
Dylan Serna | The ADU Realtor | eXp Realty | DRE #02217359
This post is general information, not legal advice. Laws summarized as of October 2026; confirm the rules for any specific parcel with the city and current state law.
