How Does an Urban Lot Split Work in LA?
An urban lot split divides one single-family parcel into two legal parcels, each of which can then carry up to two units. It is processed ministerially, which means the city checks it against the standards and approves it if it complies, with no hearing and no discretion.
Three things decide whether a given lot can do it. The two parcels have to clear both size tests. The applicant has to sign an affidavit committing to live in one of the units for at least three years. And the parcel must not itself be the product of an earlier SB 9 split, nor sit next to one the same owner has already split.
What it is not is a quick paperwork exercise. A split needs a survey and a recorded parcel map, and the conditions ride along with both new parcels afterward. The SB 9 checker will tell you whether the size tests are satisfiable for a given address.
The size tests, and which one bites
Each of the two parcels has to be at least 1,200 square feet and at least 40% of the original lot. The 40% is the part worth reading twice. The statute describes a split into approximately equal areas and then expressly permits one parcel to be as small as 40% of the original, so a split does not have to come out anywhere near even: 40/60 is inside the rule. The floor decides the smallest lot that can be divided at all, which is 2,400 square feet for two parcels of 1,200. A local ordinance may allow a smaller minimum lot size than the 1,200, and this site holds no confirmed record of one for Los Angeles, so a lot that fails on size is worth asking City Planning about rather than treating as settled.
In practice the floor is what owners of small lots run into and the share is what owners of large ones do. If you have been picturing the back third of a deep lot becoming its own parcel, the 40% is the number to check first, because a third is below it.
LA SB 9 Lot Split & Duplex Checker
Check an address against SB 9's two pathways: the urban lot split and the two-unit development. What each one allows, which exclusions apply, and what the city has to let you build.
The owner-occupancy affidavit
An urban lot split requires you to sign an affidavit of intent to occupy one of the units as your principal residence for at least 3 years, and those 3 years run from the date the lot split is approved rather than from the recordation of the parcel map. Those are different dates and the gap between them is yours to plan around. A community land trust and a qualified nonprofit corporation are exempt. All of that is Government Code 66411.7(g). The affidavit is a condition of the application rather than a test your property passes or fails, so an owner unwilling to sign it has not been turned down: they have run into a commitment they can decide whether to make.
It is a commitment made at application rather than a test of the land, which is why this site treats an owner unwilling to sign it differently from an excluded parcel. The route is open to the property and closed by the owner's own choice, and those are two different sentences to be told.
Once it is approved
A unit created under SB 9 may only be rented for terms longer than 30 days, so it cannot be put on the short-term rental market. That is worth knowing before the project is costed, because it rules out the income some owners are counting on.
The conditions attach to both new parcels and survive the sale, which is the part that catches people. A buyer takes the parcel with the SB 9 conditions on it, including the restriction on splitting it again, and that is a thing to disclose rather than a thing to discover.
A split also does not by itself get you any buildings. It gets you two parcels, each of which may carry up to two units, and each unit still needs its own permit and still has to fit the setbacks, height and coverage the city applies.
Common questions
Do both new parcels have to be the same size?
Can I split a lot I just bought?
Can I sell one of the two new parcels?
Related guides
- What Is SB 9 in Los Angeles?SB 9 is the California law that lets owners split a single-family lot or add a second unit. What it does, what it does not do, and how Los Angeles applies it.
- Can I Build a Duplex on My Single-Family Lot in LA?SB 9's two-unit pathway lets you add a second unit to a single-family lot in Los Angeles. What it allows, what the city has to permit, and what stops it.
- SB 9 or an ADU: Which Fits My Lot?SB 9 and the ADU statutes solve different problems. What each one allows in Los Angeles, what each one costs you in commitments, and when to use which.
- Why Some LA Lots Are Excluded From SB 9The exclusions that put an LA lot outside SB 9, the conditions that carry an exception, and the difference between the two. Historic, environmental, fire and fault.
The rules on this page were last checked by a person on October 16, 2026