ORANGE COUNTY, Oct. 26, 2026 — With about nine weeks until AB 956 takes effect, Orange County cities are at very different stages of updating their ADU ordinances. Dana Point just finished its update. Tustin has written new limits into its code. Others are still drafting. Most of these updates were written for the 2026 laws, not for the two-detached-ADU rule coming January 1.
For investors, the update matters less than you’d think. When a city’s ADU ordinance doesn’t match state law, state law wins. Here’s where things stand and what it means if you’re buying a lot for its ADU potential.
What Happened
On September 29, Gov. Newsom signed AB 956 (Chapter 791, Statutes of 2026). Starting January 1, 2027, cities must approve two detached new-construction ADUs on a single-family lot, up from one. Each can be capped at 800 square feet, with 4-foot side and rear setbacks. The same day, he signed SB 1117, which limits impact fees to the square footage above 750. My full breakdown of both bills is in Newsom Signs AB 956 and SB 1117.
Cities now have to rewrite their codes again. Many only just finished updating for the 2026 laws.
OC City ADU Ordinance Tracker
This is based on public council reports. Status can change at any meeting, so confirm with the planning counter before you write an offer.
| City | Latest action | What changed | Status |
|---|---|---|---|
| Dana Point | Second reading, late Sept. 2026 | Permanent ordinance replacing an urgency ordinance, written to answer HCD comments | Effective in 30 days if HCD raises no substantial issues |
| Tustin | Ordinance 1578, introduced July 2026 | Up to 3 ADUs plus a JADU on a single-family lot; up to 8 detached ADUs on existing multifamily | Set for second reading |
| Placentia | Ordinance O2026-01, Feb. 2026 | Review deadlines, clearer appeals, JADU sprinkler rule (SB 543, AB 462) | Introduced 5–0 |
| San Juan Capistrano | Code amendment started March 2026 | Alignment with AB 462 and JADU bills | Drafting for Planning Commission |
| Aliso Viejo | Urgency ordinance, Dec. 2025 | Title 15 updated for 2026 state laws | Adopted |
| Huntington Beach | Ongoing litigation with the state | History of HCD violation notices on ADU rules | Expect friction |
Notice the pattern. These updates are aimed at last year’s laws. Even a city that just adopted a new ordinance will probably need another one for AB 956.
Why a Late Ordinance Doesn’t Block Your ADU
Under Government Code Section 66316, a local ADU ordinance that conflicts with state law is null and void, and the city must apply state standards until it adopts a compliant one. HCD uses this. In an August 2025 notice of violation to Dana Point, HCD found eight earlier findings unresolved, including rules that allowed only one ADU type per lot and owner-occupancy requirements. It warned it could refer the city to the Attorney General.
So starting January 1, a two-detached-ADU application in any OC city should be reviewed under state law, whatever the local code says. The catch is practical. Counter staff, forms and plan-check lists often lag by months, and Irvine formally opposed AB 956. Expect some cities to push back at first.
What This Means for Buyers
Buy the lot for 2027
A 6,000 to 7,500 square foot lot with a deep yard or alley access may hold two detached units next year. Whether two 800-square-foot units actually fit depends on lot coverage, separation and fire access, not just the law. I’m seeing the most of these lots in Garden Grove, Anaheim and Santa Ana, where tract lots run deeper than in newer cities.
Check the city, not just the state
State law sets the minimum, and some cities already allow more. Tustin’s 3-plus-JADU limit is one example. Garden Grove has its own fee and setback rules, which I cover in the Garden Grove ADU ordinance guide. For Tustin and nearby cities, see Orange vs. Tustin vs. Villa Park.
Huntington Beach is still a wild card
State law applies there too. But the city has fought Sacramento on housing for years, so build extra time into any plan. More in Huntington Beach’s housing law fight.
Multifamily owners get the most new room
Tustin’s limit of up to 8 detached ADUs on existing multifamily follows SB 1211. That’s why duplexes and fourplexes on large lots are the best ADU buys in OC right now. Browse current options on the Orange County duplex page.
What to Do Before You Close
- Pull the city’s current ADU ordinance and the date it was adopted.
- Check HCD’s ADU page and ordinance review letters for any notice against that city.
- Ask planning staff in writing how they’ll process a two-detached-ADU application after January 1.
- Confirm the lot physically fits both units, using my escrow ADU verification checklist.
- On the application, cite Government Code Section 66323(a)(2) as amended by AB 956. Bill text is on California Legislative Information.
What’s Next
Expect a wave of AB 956 ordinances in the first half of 2027, plus HCD letters to cities that don’t comply. I’ll update this tracker as councils act. If you’re looking at a lot in Costa Mesa, Fullerton or Orange and want to know what it can hold in 2027, that’s what we cover on a call.
This is general information, not legal advice. Dylan Serna is a licensed real estate agent, not an attorney.
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