Lot Splits and California's Newer Housing Laws: Questions to Ask

A possible SB 9 lot split can change what a lot is worth to a buyer, but only if the parcel qualifies and the buyer can actually use it. California Government Code 66411.7 requires cities and counties to approve a qualifying urban lot split in a single-family residential zone without discretionary review, yet the parcel must pass a list of conditions and the applicant must sign an affidavit of intent to live in one of the units for at least three years. Before you count a split in your price, ask whether your parcel qualifies, who could use the split, and whether the offer in front of you priced it at all.

This article is part of the land, lots and small multifamily section. It is written for owners deciding whether to sell, not for owners planning to build, and it describes the statutes as they read today. Zoning and eligibility for a specific parcel are questions for the city or county planning department.

What SB 9 actually is: two sections, two different tools

"SB 9" is the common name for two sections of the Government Code that work together but can also be used apart.

• Section 65852.21, the two-unit development. On a qualifying parcel in a single-family residential zone, the local agency must ministerially approve a development of no more than two residential units, without a hearing. One new unit added to one existing unit counts.
• Section 66411.7, the urban lot split. On a qualifying parcel in a single-family residential zone, the local agency must ministerially approve a parcel map that splits the lot into two parcels of roughly equal size. Each new parcel must be at least 1,200 square feet unless the city or county allows smaller, and neither may be smaller than 40 percent of the original lot.

Used together, the two sections can mean up to two units on each of two new parcels. The lot split section says the local agency is not required to allow more than two units on a parcel created this way, and the two-unit section says the agency need not permit an accessory dwelling unit or junior unit on a parcel that uses both sections.

QuestionTwo-unit development (65852.21)Urban lot split (66411.7)

Zone required

Single-family residential

Single-family residential

Kind of approval

Ministerial, no hearing

Ministerial parcel map

Owner-occupancy affidavit in the text

No

Yes, from the applicant

Tenant history limits

Yes

Yes

Short-term rentals of new units

Not allowed

Not allowed

Who confirms eligibility

City or county planning

City or county planning

Questions to ask about your parcel

Every one of these has a yes or no answer, and the planning department for your parcel is the place to get it. If the parcel is inside a city, that is the city. If it is unincorporated, it is the county.

1. Is it in a single-family residential zone? Both sections apply only there. A lot already zoned for more units is governed by its own zoning, not by SB 9.
2. Is the city, or the unincorporated area, inside a Census urbanized area or urban cluster? Both sections require it.
3. Does the parcel hit any excluded site condition? Both sections borrow a list of site conditions from Government Code 65913.4, as that section read on September 16, 2021. Ask the planning department to check your parcel against that list rather than guessing.
4. Is it historic? A parcel with a listed landmark, or a contributing structure in a historic district, can be excluded.
5. Who has lived there in the last three years? Neither section allows demolishing or altering housing that was occupied by a tenant in the last three years, or housing under rent control or an affordability covenant. A parcel withdrawn from the rental market under the Ellis Act within 15 years is also out.
6. Has it been split before? A parcel created by an earlier urban lot split cannot be split again this way, and an owner who already split an adjacent parcel under this section cannot split this one.

If the answers are uncertain, write that down as uncertain. A buyer will treat an unknown as a risk and price it that way, so the more of these you can answer with a letter or an email from planning, the less room there is for a discount.

Who can actually use a split? The affidavit question

This is the question most sellers miss. Section 66411.7 requires the applicant for an urban lot split to sign an affidavit stating that they intend to occupy one of the housing units as their principal residence for at least three years from approval. Community land trusts and certain qualified nonprofit corporations are exempt. The two-unit section, 65852.21, contains no such affidavit in its text.

For a seller, that changes who might pay for split potential.

• An investor buying to resell or rent usually cannot honestly sign an intent-to-occupy affidavit, so its cash offer will tend to price the parcel on what it can do without a split: the current house, a second unit under the two-unit section if the parcel qualifies, or other options under the city's rules.
• An owner-occupant buyer who plans to live in one unit could be the applicant, so on the open market that buyer may value a qualifying split more.
• You, before selling, could apply for the split yourself, but you would be signing the affidavit. What that means if you then sell is a legal question for a real estate attorney, not something to settle with a buyer.

What a possible split does to a cash offer

Ask the buyer to say, in writing, which of three things the offer assumes: no added units, a second unit on the existing lot, or a split. Each one implies a different set of costs the buyer has deducted: planning and survey work, a parcel map that meets the Subdivision Map Act, utility connections, and the time all of that takes. An offer that quietly prices a split you could never get approved is as unhelpful as one that ignores a second unit the zoning clearly allows.

The split itself also comes with conditions the agency may impose: easements for public services and facilities, access to the public right-of-way, and, unless the parcel is near major transit or a car share vehicle, up to one off-street parking space per unit. Whether a narrow or deep lot can meet those is part of what the buyer is pricing. For how the rest of a land price is built, see how vacant land is priced.

When listing nets more

A qualifying split is one of the clearer cases where the open market can pay more than an investor. If planning has confirmed in writing that your parcel qualifies, the lot is large and regular enough to split cleanly, and you have time to market it, a listing that reaches owner-builders and owner-occupants may net more than a cash sale. If eligibility is doubtful, the house needs work, or you need a set date, the as-is cash number may be the better one. Two numbers on one sheet are how you tell; see cash offer vs. listing.

The open-market read on that sheet is a preliminary estimate, not an appraisal. It is not a certified appraisal of the lot as split, and no buyer's number is a ruling on eligibility.

Selling in Claremont

For Claremont parcels, Mr. Claremont, the listing practice of licensed agent Anthony Grynchal, already covers what the city's lots can and cannot do in SB 9 lot splits in Claremont. Read that for the Claremont specifics; the questions on this page apply to any parcel in California.

What this looks like in practice

These are the kinds of files that come in, described without names or figures.

• An owner of a large lot in a single-family zone who heard a neighbor talk about splitting, and wants to know whether a cash offer priced that or ignored it.
• A long-time landlord whose house was rented within the last three years, which changes what can be demolished or altered, and so what a buyer can plan.
• Heirs who want to know whether to apply for a split before selling, which becomes a question for the estate's attorney once the affidavit is explained.

Next step

If you own a lot where a split or a second unit might be possible, the land, lots and small multifamily page explains what to send, or call (909) 498-3977. The cash offer comes from an independent buyer or investor and states which assumption it priced; the open-market read sits beside it, with the comps and the net. For the wider picture, including small buildings, start with selling land, a duplex or a small apartment building for cash. There is no cost and no obligation to get the two numbers and the written report.

Sources

• California Government Code 66411.7 (urban lot splits: eligibility, ministerial approval, permitted conditions, owner-occupancy affidavit), text read on California Public Law: california.public.law, accessed November 6, 2026
• California Government Code 65852.21 (two-unit developments in single-family residential zones), text read on California Public Law: california.public.law, accessed November 6, 2026

Mr. Cali Offers is not a law firm and does not decide whether a parcel qualifies; ask the city or county planning department and your own attorney. Cash offers come from independent buyers and investors who buy for their own account and may resell for profit; a cash offer is generally below what the open market would bring. Any value shown is a preliminary estimate, not an appraisal. Nothing here is legal, tax or financial advice.