SB 1090 Pauses Altadena Lot Splits Through 2030. Not ADUs.
Chris Koss, AIA|Published July 16, 2026
A bill to keep predatory developers out of fire-scarred Altadena would pause SB 9 lot splits in ZIP 91001 through 2030. It spares your backyard ADU but closes a tool some cash-short survivors were counting on.
Photo: Altadena recovery after the Eaton Fire. CalMatters.
Andrew Post's parents lost their house on North Marengo Avenue, and the typical Altadena family that wants to rebuild is short about $550,000 after insurance. Now a state bill would remove one of the few tools that could close that gap. SB 1090 cleared two Assembly committees on July 1 and would exempt Altadena's ZIP codes from California's SB 9 lot-split and SB 1123 subdivision laws through January 2030, while leaving accessory dwelling units entirely alone.
The short version:
- SB 1090 would bar SB 9 two-unit projects and urban lot splits, plus SB 1123 subdivisions, in ZIP codes 91001 and 91003 for applications filed from January 1, 2027 through January 7, 2030.
- It does not amend California's ADU or JADU statutes, so a detached ADU or a junior ADU stays ministerial on a burned Altadena lot.
- Of 5,645 Altadena parcels with damaged or destroyed homes, only 52 have filed SB 9 permits so far. Fourteen are under construction and two are finished.
What the bill actually does
Senate Bill 1090, carried by Sen. Sasha Renee Perez with Altadena Assemblymember John Harabedian as principal coauthor, amends four sections of the Government Code. All four govern the same thing: turning one single-family lot into more than one saleable piece. SB 9 (Sections 65852.21 and 66411.7) lets an owner build a second unit and split the parcel in two. SB 1123 (Section 66499.41) makes it easier to subdivide vacant land and sell the pieces off. The bill would switch off the ministerial, no-hearing approval those laws normally guarantee, but only inside Altadena, and only for applications filed in a narrow window that opens in 2027.
Perez frames it as protection. Altadena, she said at a press conference, should not be "a playground for people who want a return on investment." Before the fire, 95 percent of the homes in the burn footprint were single-family, according to a UCLA analysis, and supporters argue the state's density laws were never written for a town that was two-thirds destroyed in a single night.
"This bill would provide that the above-described ministerial approval requirements do not apply to an application for a proposed housing development or map located in ZIP Code 91001 or 91003 and submitted on or after January 1, 2027, and before January 7, 2030, except as specified." SB 1090, as amended July 2, 2026, Legislative Counsel's Digest.
Your ADU is not in this bill
Read the list of amended sections again: 65852.21, 65852.28, 66411.7, 66499.41. None of them is Section 65852.2, the state statute that makes accessory dwelling units ministerial, and none is 65852.22, which covers junior ADUs. If you are a first-time ADU client on a burned Altadena lot, SB 1090 does not reach your backyard unit. A detached ADU, a garage-footprint conversion, or a junior ADU inside the main house is approved under the separate ADU law, on the same 60-day clock it always had. The bill freezes the lot split, not the second home.
That distinction matters more here than almost anywhere, because Altadena is already leaning on ADUs to house families while the main house is under construction. Five days ago we covered LA County's Eaton Fire ADU grant, which pays survivors to do exactly that. SB 1090 leaves that path open. What it does not do is give a cash-strapped owner a way to sell part of the land.
Who wins and who loses
The winners are the residents, and there are many, who watched renderings of boxy fourplexes land on a street of bungalows and decided that was not the Altadena they were burned out of. The temporary, one-ZIP scope of the bill is aimed squarely at out-of-town speculators, and it will slow them down.
The losers are quieter. Andrew Post's retired parents filed in June to split their North Marengo parcel, hoping to sell half and fund the rest of their build. Azeen Khanmalek of Abundant Housing LA calls a lot split a "potential tool and pathway" for owners who are underwater, not a threat. Turn off SB 9 in 2027 and you turn off that lump sum for anyone who has not filed yet. The ADU the bill leaves standing produces monthly rent, slowly. It does not produce $550,000 at closing.
Our read: SB 1090 protects Altadena's character and its ADU rights at the same time, which is the part nobody is arguing about. The real cost is that it closes the one door, splitting a lot and selling the far half, that could have funded some survivors' return. Whether that trade is worth it depends entirely on whether you were counting on the door.
The cross-street check. This is a California-shaped fight, and the other two metros do not have it in the same form. San Francisco never saw an SB 9 lot-split rush, because single-family zoning is a thin slice of the city; the exit-value tool there is the 2025 ordinance that lets an owner sell a new in-law as a condominium, which we covered when it passed. New York City has no SB 9 analog at all. Its City of Yes accessory units attach to the home and cannot be carved off and sold as a separate deed, so a Brooklyn owner rebuilding after a disaster would face a financing question closer to a cash-out refinance than a lot split.
What to watch
SB 1090 passed both the Assembly housing and local government committees with near-unanimous votes and no fiscal committee referral, so it moves quickly. The version amended on July 2 is the one to read, and the ZIP-code window (January 1, 2027 to January 7, 2030) is the number that decides whether your application lands inside or outside the freeze. If you are weighing a lot split in Altadena, the calendar now matters as much as the budget.
If you are rebuilding in the burn area, three official resources are worth a bookmark: the LA County recovery hub for permit and rebuild help, the LA County Regional Planning ADU program for the unincorporated-county ADU counter and free plans, and the Legislature's own status page to track where SB 1090 actually stands before you file anything.
The Assembly floor takes it up next, and the bill that reaches the Governor's desk may not be the one Altadena is arguing about today.
Elsewhere on the ADU beat
- Altadena's expanded wildfire building-code zone now sweeps in hundreds more rebuilds under Chapter 7A, with the county set to adopt it by late July, LAist.
- New York City finalized its rules for legalizing basement and cellar apartments, moving the long-promised pilot toward open applications, 6sqft.