Most people have never heard of these two laws, and that is a shame, because they are some of the most useful housing rules California has passed. If your lot qualifies, you can build up to 10 small homes with no public hearing and no environmental review. Here is the honest version of how that works, and the part that quietly stops people.
SB-684 and SB-1123 make up the Starter Home Revitalization Act. Together they let you split a lot and build up to 10 homes on it through what the state calls a ministerial process. Ministerial is the word that matters. It means the city does not get to hold a hearing, take a vote, or run a long environmental review. If your project checks the boxes, they have to approve it.
The city gets 60 days to approve or deny a complete application. If they miss that window, the project is deemed approved by default. That alone removes the single biggest source of delay and uncertainty in small development, which is the discretionary hearing where a project can die for reasons that have nothing to do with the rules.
There are two tracks, and they took effect on different dates.
In both cases the lot has to sit inside a city or urban area and be surrounded by other developed land. The new parcels have to be at least 600 square feet each. And since July 2025, a city is allowed to let you add ADUs that do not count against your 10-home limit, though that part is the city's choice, not a guarantee.
The word that decides most single-family deals is vacant. Under SB-1123, vacant has a specific meaning. The lot cannot have a permanent habitable structure on it, it cannot be under rent control or an affordability covenant, and it cannot have been lived in within the last five years. A lot that looks empty is not always vacant in the eyes of the law, and a lot with an old cottage or a recent tenant can fall out of the program entirely.
This is exactly the kind of detail that does not show up until late, after someone has already spent money on a plan. The size math, the urban-surroundings test, and the vacancy history all have to line up before any of the speed and certainty kicks in.
Put it next to the other tools and you see the picture. SB-9 splits your lot. SB-684 and SB-1123 let you put up to 10 small homes on it with no hearing. Build them with fast factory-built methods and the timeline shrinks again. The ceiling on what a modest lot can become is much higher than most owners think, and the path is far more predictable than the old way of begging a planning commission for a yes.
That is the real question, and it turns on the vacancy history, the zoning, and the parcel math for your specific property. That is exactly what a free ClearPath Read checks, before you spend a dollar on plans.
Get your free ClearPath ReadSources: California SB-1123 bill text (leginfo.legislature.ca.gov), Allen Matkins legal alerts on the Starter Home Revitalization Act, California YIMBY. This page is general information, not legal advice. Whether a specific parcel qualifies depends on its facts and the local jurisdiction.