For decades the answer was simple: an ADU is part of your property, and it sells with the house. AB 1033 changed that. In the City of San Diego since August 2025 — and unincorporated San Diego County since April 4, 2026 — you can convert an ADU into a condominium and sell it separately, with its own deed and its own buyer.
The 60-second version
Yes — in the City of San Diego and unincorporated San Diego County, you can now sell an ADU separately from your main home. AB 1033 (2023) is an opt-in state law: it lets a city or county allow ADUs to be sold as condominiums. The City of San Diego opted in effective August 22, 2025. The County Board of Supervisors adopted its ordinance unanimously on March 4, 2026, effective April 4, 2026.
It is not a lot split. Your property becomes a small condominium — two (or more) units on one lot, each with its own deed and Assessor’s Parcel Number. Getting there takes a parcel map, separate utility metering, written consent from every lender on the property, and recorded CC&Rs. The County estimates a full conversion can take two to three years — which is exactly why the smart move in 2026 is deciding before you build whether your ADU should be condo-ready.
- City of San Diego: allowed since Aug 2025
- County: effective April 4, 2026
- Condo conversion, not a lot split
- Separate meters + lender consent required
- Rules for other cities vary — confirm locally
What AB 1033 actually did
Before AB 1033, California law was blunt: an ADU could not be sold or otherwise conveyed separately from the primary residence. You could build one, rent it out, house family in it — but the day you sold, it went with the house. AB 1033 gave every city and county the option to lift that restriction by adopting a local ordinance that treats the ADU and the primary home like condominium units.
That word “option” matters. AB 1033 did nothing on its own. Each jurisdiction has to opt in, and each one writes its own rules. That’s why the answer to “can I sell my ADU?” depends entirely on which side of a city boundary your lot sits — the same question that already decides your size caps, setbacks, and permit track.
Where you stand in San Diego, jurisdiction by jurisdiction
| Jurisdiction | Can you sell an ADU separately? | Notes |
|---|---|---|
| City of San Diego | Yes — since August 22, 2025 | Adopted as part of the City’s 2025 ADU reform package; condo conversion process applies |
| Unincorporated San Diego County | Yes — since April 4, 2026 | Adopted unanimously March 4, 2026; County guidance issued April 2026; follow-up homeownership rules under review (see below) |
| Encinitas, Carlsbad, Oceanside & other independent cities | Varies — confirm locally | Each city must adopt its own AB 1033 ordinance; status changes frequently. We verify your city’s current position as part of feasibility |
If your property is in a North County city or another independent jurisdiction, don’t assume either way. Opt-ins are happening city by city across California, and a city that hasn’t adopted an ordinance today may adopt one during the year-plus you’d spend designing and building anyway. That cuts in favor of building condo-ready even where separate sale isn’t allowed yet — more on that below.
The rules are still moving — in the direction of more strings, not fewer. In June 2026 the County began considering follow-up options intended to steer separate-sale ADUs toward homeownership rather than investors: giving an existing renter priority when the ADU is sold, and requiring owner-occupancy for the first year or longer. None of this is final as of July 2026, but the pattern is familiar from the City’s Bonus Program rollback: early adopters got the most flexible version of the rules. If separate sale is part of your long-term plan, there’s a real argument for getting the project moving while the requirements are at their lightest.
How the conversion actually works
This is a condominium conversion under the Subdivision Map Act — the same legal machinery used when an apartment building converts to condos, scaled down to a house and its ADU. The land stays one lot; ownership of the structures is divided. Here’s the honest version of what it takes:
- Tentative parcel map A licensed surveyor or civil engineer prepares a condominium map application for the jurisdiction. This is a real subdivision-level entitlement, not a form at the permit counter.
- Separate utilities AB 1033 conversions require independent metering — water, sewer, gas, and electric — for each unit. If your ADU shares services with the house (most existing ones do), separating them after the fact is trenching, panel work, and utility coordination that can run well into five figures.
- Lender consent, in writing Every lender, deed-of-trust holder, and lienholder on the property must consent before a condominium map can be recorded. Lenders can say no, or attach conditions. If you have an existing mortgage, this is usually the single hardest step.
- CC&Rs and a two-unit HOA The units will share land, so recorded covenants govern maintenance, insurance, access, and cost-sharing — effectively a very small homeowners association between you and your future buyer.
- Separate APNs and sale Once the condominium plan records, the County Assessor issues each unit its own parcel number. The ADU can then be sold, financed, and taxed as its own home.
County staff estimate a complete conversion can take two to three years from start to recorded map, driven by utility separation, mapping, and legal work. We flag that number early with clients because it reframes the decision: this isn’t a quick exit strategy, it’s an asset strategy — and most of its cost disappears if you plan for it during construction instead of retrofitting later.
Build now, decide later: the condo-ready ADU
Here’s the practical takeaway for anyone planning an ADU in San Diego in 2026. You don’t have to commit to selling your ADU. You just have to avoid building it in a way that forecloses the option. The expensive parts of an AB 1033 conversion — utility separation above all — cost a fraction as much when they’re designed in from day one:
| Decision | Why it matters for separate sale |
|---|---|
| Dedicated utility laterals & meter locations | Separate water, sewer, gas, and electric service is a hard requirement. Trenching and stubbing for it during construction is routine; retrofitting it later means tearing up a finished yard |
| Independent access and address | A unit that will be owned by a stranger needs its own clear path from the street, not a walk through your patio |
| Fire separation & building placement | Detached units with code-compliant separation convert most cleanly; positioning affects mapping and insurance |
| Full-function layout | A future buyer’s lender appraises the ADU as a standalone home — full kitchen, laundry, and storage all support value |
We now walk every design client through this decision at feasibility: is this ADU family housing, a rental, or a potential asset you might sell? The answer changes where the meters go — and that’s a decision worth getting right the first time. It also interacts with your property tax picture, since a converted ADU gets its own assessment, and with how you finance the build, since the lender you choose today is the lender whose consent you’ll need tomorrow.
AB 1033 condo conversion vs. an SB 9 lot split
Homeowners researching this often run into SB 9 and assume it’s the same thing. It isn’t, and the right tool depends on your lot and your goal:
| AB 1033 (ADU condo conversion) | SB 9 (urban lot split) | |
|---|---|---|
| What divides | Ownership of the units; the land stays one lot | The land itself splits into two lots |
| Where it works | Only in jurisdictions that opted in (City of SD, County unincorporated) | Single-family zones statewide, subject to SB 9 criteria |
| Ongoing relationship | Shared CC&Rs and a small HOA with the buyer | Clean separation — two independent lots |
| Owner-occupancy | Not currently required in the City; County considering first-year requirements | Three-year owner-occupancy affidavit required for the split |
| Typical fit | Lots that can’t split, or owners who want to keep the land whole | Larger lots that meet split criteria and owners wanting a full exit |
We compared the two paths in more depth in SB9 vs. ADU. The short version: AB 1033 opens separate sale to thousands of San Diego lots that could never qualify for an SB 9 split.
What this does to the math on building an ADU
Until now, an ADU’s return came from two places: rent and added property value. AB 1033 adds a third — a realizable exit. A detached ADU in the City of San Diego that might sell as an entry-priced condo is a different financial object than the same building that can only ever be a rental. It changes the conversation for the three kinds of clients we see most: families building for aging parents (the unit can eventually be sold rather than sitting empty), rental investors (an exit option de-risks the hold), and empty-nesters downsizing into the ADU (who could one day sell the unit they’re not living in — in either direction).
We’d stop short of the hype you’ll see elsewhere. The conversion is slow, lender consent is a genuine obstacle on mortgaged properties, and the County may attach owner-occupancy strings before the year is out. But as a free option you can bake into a build you were doing anyway, it’s one of the strongest developments in San Diego ADU law in years. Budget-wise, the build itself is unchanged — our 2026 cost guide still applies; condo-ready provisions add modest, mostly-utility line items that we price per lot.
Wondering if your lot pencils for a sellable ADU?
We’ll check your jurisdiction’s AB 1033 status, your lot’s constraints, and what condo-ready would add to your build — free.
AB 1033 FAQ
Can I sell my ADU separately from my house in San Diego?
Yes, in two jurisdictions: the City of San Diego has allowed it since August 22, 2025, and unincorporated San Diego County since April 4, 2026, both under AB 1033. The ADU is converted into a condominium with its own deed and parcel number, then sold. Other San Diego-area cities must each adopt their own ordinance — status varies, so confirm your specific city before planning around a sale.
Is an AB 1033 conversion the same as splitting my lot?
No. Your land stays one lot. The conversion divides ownership of the structures, like a condominium — you and the ADU buyer each own your unit and share the lot under recorded CC&Rs. An SB 9 urban lot split, by contrast, divides the land itself into two separate lots and has its own eligibility rules.
What does it take to convert an ADU to a sellable condo?
A tentative parcel map prepared by a surveyor or engineer, separate utility meters for water, sewer, gas, and electricity, written consent from every lender and lienholder on the property, recorded CC&Rs governing the shared lot, and a separate Assessor’s Parcel Number for each unit. County staff estimate the full process can take two to three years.
Do I need my mortgage lender’s permission to sell my ADU?
Yes. AB 1033 requires written consent from every lender, deed-of-trust holder, and lienholder before a condominium map can be recorded. Lenders can decline or impose conditions. Owners with no mortgage have the cleanest path; if you’re financing the ADU build, the loan you choose now is the consent you’ll need later, which is worth factoring into your financing decision.
Should I build my ADU differently if I might sell it someday?
Yes — this is the biggest practical takeaway. Separate utility laterals and meter locations, independent street access, code-compliant fire separation, and a full-function layout are all far cheaper to include during construction than to retrofit. Building condo-ready keeps the sale option open without committing you to it, even in cities that haven’t opted in to AB 1033 yet.
Will the ADU have its own property taxes after conversion?
Yes. Once the condominium plan records, the County Assessor issues the ADU its own parcel number and it’s assessed, taxed, and financed as a separate home. Before any conversion, a new ADU simply adds its construction value to your existing assessment — it does not trigger reassessment of your main house.
Keep exploring
SB9 vs. ADULot splits compared with ADUs
Financing your ADUSix options, ranked for 2026
ADUs & property taxesWhat changes on your bill
What an ADU costs2026 budget ranges
Free feasibility checkRun the numbers on your lot
Not legal advice. This page summarizes AB 1033 (2023) and its local implementation in the San Diego region as we understand it for general informational purposes. Condominium conversion involves subdivision mapping, title, and lending questions that require a licensed surveyor, real-estate attorney, and your lender — we design and build; we coordinate with those professionals but don’t replace them. Rules change frequently and local implementation varies; we verify current requirements for your specific jurisdiction and lot before design. Prepared by IL Total Design & Build (CSLB #1058676). Last updated July 2026.
Sources: California AB 1033 (Ting, 2023), Government Code §66342; City of San Diego 2025 ADU ordinance amendments (effective Aug. 22, 2025); County of San Diego Board of Supervisors ADU Ordinance Amendment (adopted Mar. 4, 2026, effective Apr. 4, 2026) and PDS “Guidance for Separate Sale of ADUs under AB 1033” (Apr. 2026); County of San Diego Planning Commission materials on separate-sale implementation options (May–June 2026).
