SB 1121: Key Points and Impacts on ADU Construction in California
n 2021, California Senate Bill 1121 (SB 1121) was signed into law to further streamline the development of accessory dwelling units (ADUs) and address California’s ongoing housing shortage. By reducing bureaucratic red tape, offering new design flexibility, and speeding up the approval process, SB 1121 aims to make it easier for homeowners across the state to build ADUs.
SB 1121 addresses some of the key challenges that homeowners face when adding an ADU to their property, helping both single-family homes and multi-family lots. This bill enhances the state's previous ADU laws and provides clarity, flexibility, and incentives to encourage ADU development. At MF ADU, we’ve compiled the key points and impacts of SB 1121, so homeowners can fully understand how this legislation affects their ADU projects.
Key Points of SB 1121
1. Streamlined Permit Process
SB 1121 accelerates the permitting process, requiring local agencies to approve or deny ADU permit applications within 60 days of submission. This significantly reduces the waiting time, which often previously stretched for several months, especially in high-demand urban areas.
Impact: Homeowners can expect faster approval times, making the process smoother and more predictable.
2. Removal of Minimum Lot Size Requirements
One of the key aspects of SB 1121 is the removal of minimum lot size requirements for ADUs on residential properties. Previously, some cities enforced minimum lot size restrictions that made it difficult or impossible to build ADUs on smaller lots. Under SB 1121, homeowners are now able to build ADUs on smaller properties, as long as the site is zoned for residential use.
Impact: This makes ADU development possible on more properties, especially in urban and densely populated areas.
3. No Setbacks for ADUs Above Existing Structures
For homeowners looking to convert or build an ADU above an existing structure (such as a garage or a detached unit), SB 1121 eliminates the setback requirements for these types of units. This allows for better utilization of available space and removes the need to adjust existing layout plans, which would have otherwise required extensive redesigns.
Impact: Homeowners can maximize the potential of their existing structures and avoid additional design costs.
4. Parking Waivers Near Public Transit
SB 1121 provides parking waivers for ADUs if the property is located within half a mile of public transit or major transit hubs. Previously, some cities required homeowners to add parking spaces when building an ADU, which often complicated the design and added costs. The waiver for parking allows for more flexible ADU designs in areas with limited parking or in high-density neighborhoods.
Impact: In urban areas or near transit routes, homeowners can build ADUs without worrying about adding parking spaces.
5. Increased ADU Size and Height Limits
SB 1121 allows for larger and taller ADUs than what was previously allowed in many cities. Under the new law, an ADU can be built up to 1,200 square feet on residential properties. The bill also provides flexibility on height limits, particularly for units that are built above garages or other existing structures. These changes offer more space for homeowners to create livable, comfortable units.
Impact: Homeowners have greater design flexibility to create larger, more functional living spaces that suit long-term needs.
6. Affordable Housing Incentives
SB 1121 encourages homeowners to build affordable housing units by offering incentives for renting ADUs to low-income tenants. The incentives help align ADU development with California’s goal of increasing affordable housing options across the state.
Impact: Homeowners who rent their ADUs to low-income tenants may qualify for incentives that lower construction costs.
Did you know?
Did you know? Under SB 1121, local cities must allow ADUs in all residential zones—even if the local zoning code previously prohibited them—making it easier than ever to build on your property.
Impacts of SB 1121 on ADU Construction
1. Increased ADU Development Across the State
SB 1121 is expected to increase the rate of ADU development statewide by making it easier for homeowners to navigate the permitting process and offering more flexibility in design. As more homeowners realize the benefits of ADUs—whether for rental income, family use, or additional living space—more properties will see these units being built.
2. Faster Returns on Investment
Faster permitting means that homeowners can begin construction sooner and start seeing returns on their investment through rental income or increased property value. The ability to add a functional and livable space quickly means homeowners can enjoy the benefits sooner rather than waiting for extended approval periods.
3. Boosting Housing Supply and Reducing Housing Shortages
By encouraging ADU development, SB 1121 helps California address its ongoing housing crisis. ADUs offer affordable housing options in established neighborhoods, reducing the need to build on undeveloped land and contributing to sustainable growth.
Conclusion
SB 1121 simplifies and accelerates the ADU development process, making it easier and more affordable for homeowners to build on their property. Whether you’re looking to add rental income, provide family housing, or increase your property’s value, SB 1121 provides the flexibility and support needed to achieve your goals.
At MF ADU, we stay updated on all legislative changes, including SB 1121, to ensure that your ADU project is not only compliant but optimized for success. Explore our prefabricated ADU models and get started on building your perfect ADU today.
FAQs
How does SB 1121 affect my ADU project?
SB 1121 streamlines the approval process, removes setback and lot size requirements, and allows for faster construction timelines.
Can I build an ADU on a small lot?
Yes. SB 1121 removes minimum lot size requirements, allowing ADUs on smaller properties.
What’s the maximum size for an ADU under SB 1121?
SB 1121 allows ADUs up to 1,200 square feet, depending on your city’s regulations.
Does SB 1121 make it easier to get permits?
Yes. The law requires cities to approve or deny ADU permits within 60 days of receiving a complete application.
Can I rent my ADU to low-income tenants?
Yes. SB 1121 encourages affordable housing and offers incentives for renting ADUs to low-income tenants.