Create a second legal parcel
For the right property, SB9 may allow one qualifying parcel to be divided into two legal lots. That can create a new real estate asset where only one existed before.
California SB9 lot split guide
What Is SB9 in California? A Homeowner's Guide to Lot Splits
California Senate Bill 9, also called the HOME Act, created a ministerial path for certain single-family properties to add primary homes, split one parcel into two legal lots, or combine both options. Eligibility still depends on state requirements, local objective standards, and the property's actual access, utilities, layout, and constraints.
Prepared by Riechers Engineering's California SB9 project team using California HCD guidance and current Government Code sources. Updated July 12, 2026.
45+ years of civil engineering experience
200+ lot split applications submitted
70+ approvals throughout California
Quick answer
SB9 can turn one eligible parcel into more options.
Senate Bill 9 is a California housing law formally known as the California Housing Opportunity and More Efficiency Act, or HOME Act. It was signed into law in 2021 and took effect in 2022. For certain single-family residential properties, SB9 can allow a two-unit development path, an urban lot split path, or both.
In plain English, it may let a homeowner divide one legal parcel into two and create additional primary residential units, if the property satisfies state law and local objective standards. The policy goal is to add housing supply inside existing residential neighborhoods while still requiring qualifying projects to meet objective safety, design, access, utility, and land-use rules.
That combined strategy is the big homeowner opportunity: one qualifying lot can potentially become two legal lots, and each resulting lot can potentially support up to two primary residential units. That is how SB9 can reach up to four primary residential units on a property that previously had one primary home, subject to property-specific rules and the final unit mix.
The important part is the word may. SB9 is not a blanket permission slip. Zoning, parcel history, tenant protections, environmental constraints, access, utilities, easements, setbacks, fire or flood overlays, and city-specific requirements can all affect whether a project is realistic.
The unit-count opportunity homeowners usually care about
Add primary housing options
SB9 can also create a pathway for additional primary residential units in single-family zones. The exact unit count depends on the project path and local objective standards.
Up to four residential units
When a qualifying urban lot split and two-unit development work together, SB9 can create a path to up to two primary residential units on each resulting lot, for up to four primary residential units total.
Sell, build, rent, or hold
Some homeowners sell the new lot, some build, some create long-term rental or multigenerational family housing, and others hold the parcel as a future asset.
Eligibility
SB9 requirements and eligibility checks before you move forward
SB9 eligibility is not something to guess from a headline or a neighbor's project. A useful review looks at the law, the city, and the actual physical property.
Single-family zoning: SB9 applies to qualifying properties in single-family residential zones, not every parcel type.
Protected housing and tenant history: SB9 includes restrictions tied to certain tenant-occupied, rent-restricted, or recently withdrawn housing.
Lot geometry: The proposed parcels must work physically and legally. Shape, frontage, access, easements, setbacks, and utilities matter.
Local objective standards: Cities can apply objective rules for zoning, subdivision, design, safety, access, and infrastructure.
Environmental and historic constraints: Certain hazard areas, protected lands, historic resources, coastal considerations, and similar constraints may limit or block a project.
Restrictions
Important SB9 restrictions homeowners should not miss
The most expensive SB9 mistakes usually happen when a homeowner assumes the law overrides every local or site-specific constraint. It does not. The state created a ministerial pathway, but qualifying projects still have to satisfy the statute and objective local standards.
Common restrictions include protected housing rules, recent tenant occupancy, parcels already created by SB9, adjacent parcels split by the same owner or actor, historic resources, certain environmental or hazard areas, and coastal considerations. For an urban lot split, the owner-occupancy affidavit can also matter unless an exception applies.
This is why Riechers treats SB9 eligibility as an engineering and land-use review, not just a form. The question is not only whether the law exists. The question is whether your parcel can satisfy the requirements in a way that creates real value.
SB9 by city
SB9 is statewide, but your local rules still decide the practical answer.
Homeowners often search for SB9 as one statewide law, but the project usually succeeds or fails at the local and parcel level. A property in Los Angeles, Alhambra, Hermosa Beach, or an unincorporated county area can face different objective standards, application steps, access requirements, public works comments, coastal issues, hillside rules, fire access concerns, or utility constraints.
That is why the best next move after learning what SB9 is should be a local feasibility check. Start with the California SB9 city guides, then compare the statewide rules with the city or county page that matches the property location.
Current local guides include Los Angeles County SB9, Los Angeles SB9, Alhambra SB9, Hermosa Beach SB9, San Diego County SB9, San Diego SB9, Chula Vista SB9, Encinitas SB9, San Francisco SB9, and Alameda SB9.
California SB9 rules should be checked against the statute and state guidance.
This guide is written for homeowners, but the legal foundation comes from California housing guidance and the Government Code sections that govern two-unit developments and urban lot splits.
California HCD SB9 fact sheet
State-level guidance on SB9 lot splits and duplexes.
Government Code Section 65852.21
The California code section addressing SB9 two-unit residential development.
Government Code Section 66411.7
The California code section addressing SB9 urban lot split requirements.
Process
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How a professional SB9 review normally works
Feasibility review
Review zoning, parcel history, title, access, utilities, setbacks, overlays, and likely city requirements before spending money on a full application.
Survey and engineering
Prepare the lot configuration, mapping, legal descriptions, and technical drawings needed to support a compliant submission.
City review and recordation
Submit the application, respond to city comments, secure approval, and complete the final map and recordation process.
Lot split, two-unit development, or both
| Path | What it means | What to verify |
|---|---|---|
| Urban lot split | Potentially divides one legal parcel into two legal parcels. | Parcel size, split ratio, access, utilities, easements, prior SB9 use, and local subdivision requirements. |
| Two-unit development | Potentially allows additional primary residential units on a qualifying single-family parcel. | Setbacks, fire access, parking rules, objective design standards, building code, and local implementation rules. |
| Combined strategy | May allow a qualifying lot split plus up to two primary residential units on each resulting parcel, creating up to four primary residential units total. | Full site feasibility, financing, utility capacity, grading, drainage, access, and long-term plan for the property. |
Value and cost
SB9 cost, value, and why the numbers depend on the lot
A lot split can create value because it may create a separate legal parcel, not just a backyard improvement. Depending on the property, homeowners may be looking at a saleable parcel, future development rights, rental income, family housing, or long-term flexibility.
That does not mean every SB9 project is worth doing. Surveying, engineering, mapping, city fees, utility planning, legal documentation, and project management all affect the economics. The right first step is to learn whether the property is a strong candidate before committing to a full project.
For the detailed cost breakdown, use the SB9 lot split cost guide.
SB9 timeline: what happens from feasibility to recorded map
Feasibility and strategy
Review whether the site is a real candidate before ordering a full application package. This is where zoning, lot geometry, access, utilities, overlays, and financial goals get checked.
Survey, engineering, and map preparation
Prepare the technical documents the city needs to evaluate the proposed parcel configuration. A weak map or missed constraint can create delays, corrections, or denial risk.
City submission and comments
SB9 uses ministerial review, but city staff still review the project against objective rules. The quality of the initial submission affects how cleanly this step moves.
Approval, final map, and recordation
Once the project reaches approval, the final map and recordation steps turn the concept into legally recognized parcels.
Common mistakes
The fastest way to lose time is submitting before the property is engineered.
SB9 applications can go sideways when homeowners or inexperienced teams treat the process like a simple paperwork exercise. The application is not the hard part. The hard part is designing a split that survives city review.
Guessing at the lot line: a proposed split can fail if it ignores setbacks, frontage, access, easements, drainage, utilities, or local objective standards.
Skipping survey and engineering review: property boundaries and technical constraints need to be clear before a permanent legal parcel map is pursued.
Assuming every city applies SB9 the same way: state law creates the pathway, but local implementation details still matter.
Riechers proof
California SB9 experience backed by completed work
Riechers Engineering's own public case studies show the practical side of SB9: navigating county objections, unlocking new parcels, resolving zoning constraints, and helping homeowners understand the real value of their property.
$650K
Santa Barbara County
Riechers challenged a negative ruling and helped create a second valuable parcel for the client.
$1.1M
Sonoma
A project using SB9 unlocked a second parcel and the potential for additional primary homes.
$50K
Napa
A client avoided costly development requirements while increasing property value through a successful split.
Real client outcomes from Riechers SB9 work
A client whose property did not meet traditional lot split requirements used SB9 to create a reported $1,000,000 parcel opportunity.
One client described the process as complicated and credited Riechers with navigating regulatory and technical obstacles.
A homeowner noted that their property value increased and encouraged others to move forward with confidence.
A steep-lot project became more valuable after a lot split opened the path for additional buildable square footage.
Video summary
What Gloria covers in the SB9 video
Gloria explains that SB9 may let qualifying California homeowners split a residential property into two legal parcels. The key idea is that the new parcel can become a real estate asset with its own options: sell it, build on it, rent it, use it for family housing, or hold it for future flexibility.
She also explains why SB9 should not be treated as a guess. Zoning, lot size, configuration, access, utilities, structural layout, city requirements, and financial goals all affect whether a split makes sense. The purpose of the feasibility review is to find out what your property can actually do before you spend serious money.
Plain-English SB9 answers
What is SB9 in California, and can I split my lot?
SB9 is California's HOME Act. It created a ministerial path for certain single-family properties to add primary units, split one parcel into two, or combine those paths when the property qualifies.
Whether you can split your lot is property-specific. The answer depends on the state statute, local objective standards, owner-occupancy and protected-housing rules, plus access, utilities, lot geometry, easements, and other site constraints.
A useful feasibility review connects those legal requirements to the actual address before you commit to surveying, mapping, design, or city fees.
California SB9 FAQ
What does SB9 allow California homeowners to do?
SB9, formally the California Housing Opportunity and More Efficiency Act, may allow an eligible single-family residential parcel to use a two-unit development path, an urban lot split path, or both. In a qualifying combined scenario, that can mean up to four primary residential units: up to two primary units on each resulting lot. The exact outcome depends on property-specific eligibility, local objective standards, and any applicable ADU or JADU interaction rules.
What are common SB9 requirements?
Common SB9 requirements include single-family zoning, legal access, utility feasibility, objective local standards, protected housing limitations, tenant history restrictions, and restrictions tied to prior SB9 use, adjacent owner activity, historic resources, environmental constraints, and coastal considerations.
How much does an SB9 lot split cost?
SB9 lot split cost depends on the property, city, surveying, engineering, mapping, application fees, utility work, and review complexity. For a deeper breakdown, review our SB9 lot split cost guide. The best first step is a feasibility review so you understand whether the property is worth pursuing before committing to a full project.
Can SB9 create two primary homes on each lot?
For an eligible urban lot split, local agencies generally must allow up to two units on each resulting lot. That is the practical "up to four units" scenario people talk about, but the site still has to satisfy legal, engineering, utility, access, and city requirements.
Does every California property qualify for SB9?
No. SB9 can be limited by zoning, protected housing rules, tenant history, historic resources, environmental or hazard constraints, coastal rules, prior SB9 use, parcel geometry, access, utilities, and city objective standards.
Is SB9 the same in every California city?
No. SB9 is statewide, but cities and counties can apply objective standards and local procedures. Before spending money on design, check the local city or county guide and then confirm the actual parcel conditions: zoning, lot layout, access, utilities, overlays, fire or coastal issues, and city review requirements.
How long does an SB9 lot split take?
Timing varies by city and property complexity. Many professional SB9 lot split projects take months because feasibility, surveying, mapping, application review, city comments, approval, and recordation all have to be handled correctly.
Do I have to build immediately after a split?
No. A homeowner may explore different strategies depending on the property and goals, including selling a newly created parcel, building later, creating rental income, planning for family housing, or holding the parcel as a long-term asset.
Find out what your lot can do.
If you are curious whether SB9 could apply to your property, the safest next move is a property-specific feasibility review with an engineering team that understands both the law and the physical site constraints.
Check SB9 Eligibility