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Senate Bill 10: What California Homeowners Need to Know About Building More Housing on Their Property

California’s housing crisis has prompted a wide range of legislative solutions aimed at increasing the state’s housing supply. Among these, Senate Bill 10, often referred to simply as SB 10, stands out as a unique and flexible tool intended to help local governments streamline housing production, particularly in urban areas and near public transit. For homeowners, developers, and cities, this bill offers the possibility to adopt zoning changes that make it easier to build more residential units on a single parcel.

While Accessory Dwelling Units (ADUs) remain a popular path for adding space, Senate Bill 10 introduces a separate process that may allow for up to 10 units per property in the right conditions. If you’re a property owner wondering whether SB 10 could help you add housing to your lot, this article will provide clear answers about how the bill works, what it means for ADUs, and how it connects to broader efforts to address California’s housing shortage.

What Is Senate Bill 10? Background and Purpose

Senate Bill 10 was introduced in 2021 by Senator Scott Wiener as part of California’s effort to combat the housing crisis. The legislature finds and declares in the bill text that the shortage of affordable housing is a critical issue affecting communities across the state. The bill authorizes cities and counties to adopt local ordinances that allow up to 10 residential units per parcel, if the property is located in a transit-rich area or an urban infill location.

SB 10 is not a mandate but an effective tool that local governments can choose to use, depending on the needs of their communities. The law was designed to offer flexibility, reduce delays from the California Environmental Quality Act, and give local leaders more authority to respond to housing needs.

How SB 10 Works

Under existing law, zoning changes that increase residential density often require time-consuming environmental review. Senate Bill 10 changes that by allowing local governments to adopt zoning ordinances that are exempt from CEQA. This means that a city or county can rezone a parcel to allow more housing without conducting a full environmental review for that zoning change.

However, this exemption only applies to the rezoning step. If a specific project proposed under the new zoning exceeds certain thresholds, it may still require CEQA analysis.

To use SB 10, the city or county must pass a formal ordinance during a formal meeting, often following a public hearing and a vote by the local committee or planning department. Once adopted, the ordinance allows for up to 10 units on eligible parcels.

Key Provisions of SB 10 Explained

Qualifying Locations

SB 10 only applies to parcels located in designated areas:

• A transit-rich area is generally defined as being within one-half mile of a major public transit stop or along a high-frequency corridor.
• An urban infill site is a location within an urbanized area, surrounded by existing development on at least 75 percent of its perimeter.

A parcel cannot be zoned under SB 10 if it falls within a very high fire hazard severity zone, unless mitigation measures are possible. Additionally, land protected by voter initiatives as public parkland or open space is not eligible.

Unit Count and Zoning Changes

Once adopted locally, SB 10 allows up to 10 residential units per parcel. This is a significant change in zoning for areas previously limited to single-family use. It does not override existing ADU regulations, meaning that additional units may be possible beyond what’s allowed under Senate Bill 10.

This increased residential density is especially useful in cities where housing shortages are most severe. It gives communities a pathway to respond more flexibly to demand.

Local Government Role

The most important detail is that SB 10 is limited by local implementation. A city or county must choose to adopt an ordinance under SB 10 during a formal meeting, and the adoption must include findings consistent with the California Constitution, including that the zoning change helps to affirmatively further fair housing.

Local adoption often involves steps such as:

• Placing the item on the general state calendar
• Holding a public hearing
• Having a planning committee vote
• Publishing a report on the plan
• Conducting outreach to affected neighborhoods

Without these steps, the bill does not apply. In short, no local ordinance, no SB 10 project.

SB 10 vs ADU Laws: What’s the Difference?

When SB 10 Might Be Better Than a Traditional ADU

For homeowners or developers interested in construction of more than two units, SB 10 may provide a valuable option. If your parcel qualifies and your local government has adopted an SB 10 ordinance, you could build a triplex, fourplex, or even up to 10 units.

This can be especially beneficial for:

• Creating housing for extended families
• Adding rental income units
• Taking advantage of transit-oriented development areas

When ADU Laws Are a Better Fit

While SB 10 is powerful, it is not always the best route. ADU laws under existing law are already adopted statewide and are typically ministerial, meaning they are permitted without discretionary review.

If you are looking to:

• Build one or two units
• Create housing for family or aging parents
• Avoid complex zoning changes or public hearings

Then ADU regulations may be the better plan.

Can You Use Both?

Yes. ADUs are not counted toward the 10-unit cap under SB 10. That means a parcel could be developed with 10 residential units through an SB 10 ordinance and still include up to two ADUs under California law.

This creates a powerful combination for increasing residential density while staying within the scope of the bill.

Benefits of SB 10 for California Homeowners

More Housing Flexibility

For property owners with large lots or underused space, SB 10 allows more strategic use of land. It enables homeowners to:

• Add units for children, in-laws, or caretakers
• Provide housing for employees or tenants
• Plan for future family needs

This flexibility supports communities that are growing and evolving.

Rental Income Potential

By allowing multiple units on a single parcel, SB 10 increases the potential for steady business income through rentals. With rising rents and housing demand, this may become a reliable revenue stream for homeowners.

Reduced Zoning Gridlock

Because SB 10 reduces the need for CEQA at the rezoning level, it cuts down on delays. This makes it easier for cities to implement zoning changes that have previously been blocked by environmental review requirements.

SB 10 and Public School Classrooms: Indirect Connections

While Senate Bill 10 primarily focuses on increasing residential density, its effect on community growth can indirectly impact public school classrooms. As more housing units are developed in transit-rich and urban infill areas, local school districts may experience changes in enrollment numbers. Planning for these shifts is essential to ensure that public school classrooms can accommodate new students without compromising educational quality.

Limitations and Risks to Consider

Local Adoption Is Required

SB 10 is not a state override. It only applies in cities or counties that choose to pass an ordinance. This means homeowners must wait for their local governments to act.

Before moving forward, check your city’s status or consult a professional team to assess adoption progress.

Environmental Review Still Applies in Some Cases

Although the act allows CEQA exemptions for the zoning ordinance itself, larger or non-ministerial projects may still require a full environmental review. This is especially true if the project involves multiple buildings, substantial grading, or is located near sensitive areas, including those affected by pollution concerns.

Not a Guaranteed Approval Path

Even if your parcel qualifies and your city adopts SB 10, the project must still follow local construction, design, and permitting rules. This includes:

• Height and setback requirements
• Parking and infrastructure plan
• Public hearings for discretionary approvals

A qualified design-build firm can help you navigate this process from start to finish.

How to Find Out If SB 10 Applies to Your Property

Step 1 – Check Local Ordinances

Contact your local department of planning or visit your city’s official website to learn whether an SB 10 ordinance has been adopted. If the answer is no, ask if any SB 10 resolutions are on the calendar.

Step 2 – Determine Parcel Eligibility

Not every parcel will qualify. Use planning maps to determine if your property is within a transit-rich or urban infill zone, and confirm that it is not in a restricted area, such as a protected subdivision or open space.

Step 3 – Work With a Local Design-Build Team

A full-service partner can help you interpret zoning, assess your parcel’s potential, create a plan, and manage the project from report to construction.

SB 10 and the Future of Housing in California

SB 10 is one of several bills aimed at solving the state’s housing shortage. By giving cities more authority to adopt zoning changes, the senate is signaling that greater residential density is part of the state’s long-term plan.

As more local governments recognize the need for growth, SB 10 may become a common tool for development across California. Homeowners who act early may benefit the most from this emerging opportunity.

Is SB 10 Right for You? Let’s Find Out Together

If you’re wondering whether SB 10 or an ADU is the best path forward, we can help. Our team at Golden State ADUs specializes in zoning research, project design, permitting, and full construction services across the Sacramento region and surrounding cities.

With more than a decade of experience and over 100 completed projects, we know how to guide homeowners through the complex world of California housing law, from formal meetings to final inspections.

Contact us today for a free feasibility report to determine if your parcel qualifies for SB 10 or ADU development. We’ll help you make the most of your land with a smart, streamlined plan.

FAQs

Does Senate Bill 10 override single-family zoning?

No. SB 10 gives local governments the option to adopt zoning ordinances that allow more residential units, but it does not automatically override zoning across the state.

Can I still build an ADU if my city adopts SB 10?

Yes. ADUs are protected under a separate law and do not count toward the 10-unit cap in SB 10.

Has Sacramento adopted SB 10?

Some cities in the Sacramento region are exploring SB 10, but not all have passed ordinances. Check your city’s current status.

How does SB 10 relate to the California Environmental Quality Act?

SB 10 allows cities to adopt zoning ordinances without a CEQA review, but individual projects may still require environmental review based on size and location.

Can I build a triplex or fourplex under SB 10?

Yes, if your parcel qualifies and your city has adopted SB 10, you may build up to 10 residential units, which includes triplexes and fourplexes.

Conclusion

Senate Bill 10 represents a significant step toward addressing California’s housing shortage by empowering local governments with the tools to increase residential density in transit-rich and urban infill areas. While the bill offers flexibility and the potential for up to 10 residential units per parcel, its success depends largely on local adoption and implementation. For homeowners and developers, SB 10 provides an opportunity to create more housing options, generate rental income, and contribute to sustainable community growth. Understanding how SB 10 works alongside other housing laws, such as ADU regulations, can help property owners make informed decisions about their development plans. As California continues to seek solutions to its housing crisis, SB 10 stands as a valuable option for communities ready to embrace thoughtful densification and smart growth.

The bill became effective in January following its passage, with the governor recorded as having signed it into law. The section of the law that details the exemption from environmental review displays clear language to guide local governments on implementation. Some critics, such as Thompson and Allen, have voiced concerns, while supporters highlight the bill’s alignment with the “ten commandments” of sustainable urban development.

Ultimately, SB 10’s order in the legislative calendar and its recorded passage declare California’s commitment to addressing housing shortages while balancing environmental and community concerns.