How SB 13 Is Changing the Rules for ADU Permits in California
Building an accessory dwelling unit (ADU) in California has often felt like navigating a bureaucratic maze. Permits, fees, zoning codes, a homeowner’s headache. But with SB 13 California in effect since January 1, 2020, the landscape is shifting. This law removes many barriers, making it easier to add an ADU or junior ADU on your property.
What Is SB 13 in California?
California Senate Bill 13 (also styled as sb‑13, 13 sb, or sb 13-251) amends state Government Code §65852.2 and Health & Safety Code §17980.12 to streamline and standardize ADU permitting across the entire state. Rather than being limited to a few cities, SB 13 applies statewide, although some localities with special regulations, such as coastal zones may have extra layers.
The Purpose of SB 13
SB 13 was designed to combat California’s housing affordability crisis by encouraging the creation of ADUs. It reduces excessive impact fees, speeds up approvals, and establishes clear minimum standards so local ordinances can’t block reasonable projects
Key Benefits of SB 13 for Homeowners
California’s SB 13 law, which took effect in 2020, has brought significant changes to the process of building Accessory Dwelling Units (ADUs). One of the key aspects of SB 13 is its focus on reducing costs and streamlining the approval process for ADUs, making it easier and more affordable for homeowners to build these units.
- No Impact Fees for ADUs Under 750 sq ft:
One of the most beneficial provisions of SB 13 is the waiver of impact fees for ADUs that are under 750 square feet. Impact fees are typically charged by local governments to fund infrastructure improvements like roads, sewer systems, and schools. By waiving these fees for smaller units, SB 13 significantly lowers the overall permit cost for homeowners. - No Owner-Occupancy Requirement:
Under SB 13, there is no owner-occupancy requirement for the first three years after building the ADU, which allows homeowners to rent out the unit without restrictions. This provides flexibility, especially for those looking to generate rental income from their ADU. - 60-Day Approval Window:
SB 13 mandates that local jurisdictions must approve or deny an ADU permit within 60 days of receiving a complete application. This standard approval timeline ensures a faster and more predictable permitting process, helping homeowners avoid unnecessary delays. - Ministerial Permit Process:
The law also ensures that the permit process for ADUs is ministerial rather than discretionary. This means that if an ADU meets the local zoning regulations and building codes, the permit cannot be denied based on subjective or political factors, providing homeowners more certainty in the approval process.
How SB 13 Impacts the ADU Permit Process in California
Here’s how the permit flow works now:
- Submit a complete application.
- Local agency has 60 days to approve or deny. If they do nothing, it’s automatically approved.
- No owner-occupancy rule (until Jan 1 2025), so you don’t have to live in either unit while developing your project
- Fees are waived or reduced: under 750 sq ft no impact fee; over that, proportional only.
- Size, parking, setback restrictions are strictly limited by SB 13.
- Convert unpermitted units: legalize within five years via streamlined process.
This is a vast improvement over prior permit pathways, which involved discretionary reviews, hearings, significant fees, and inconsistent local rules.
Exemptions and Reductions in ADU Permit Costs Thanks to SB13
- Faster Approval Process: The 60-day approval requirement helps homeowners avoid delays and additional costs associated with long wait times.
- Impact Fees Waived: ADUs under 750 sq ft are exempt from impact fees, which can save thousands of dollars in some cases.
- Reduced Plan Review Fees: Many cities offer reduced fees or simplified procedures for smaller ADUs following SB 13 guidelines.
SB 13’s Impact on ADU Permits
| Provision | Impact on Costs and Process |
|---|---|
| No Impact Fees (Under 750 sq ft) | Saves homeowners thousands of dollars in impact fees for smaller units. |
| No Owner-Occupancy Requirement | Flexibility to rent out the ADU without restrictions until 2025. |
| 60-Day Approval Window | Speeds up the process, reducing delays and the associated costs. |
| Ministerial Process | Ensures clear approval if the ADU meets code, eliminating discretionary delays. |
Tip: If you’re planning to build a smaller ADU (under 750 sq ft), SB 13 offers significant savings, especially with the waiver of impact fees and the reduced permit processing time. Be sure to take advantage of these provisions when designing your ADU.
Frequently Asked Questions About SB 13 in California
Did SB 13 pass in California?
Yes, SB 13 did pass in California. It was signed into law in 2019 and took effect on January 1, 2020. The goal of the law is to make it easier and more affordable for homeowners to build Accessory Dwelling Units (ADUs), like backyard homes or garage conversions.
What are the requirements under SB 13 for ADUs in California?
SB 13 sets rules that help simplify the process. Some of the main requirements include:
- ADUs up to 800 sq ft, 16 ft high, and with 4 ft setbacks must be allowed—even if local zoning says otherwise.
- ADUs under 750 sq ft don’t have to pay impact fees.
- Cities must approve or deny applications within 60 days.
- No requirement to replace parking if you convert a garage (in many cases).
- Setback rules must be reasonable (like 4 feet from property lines).
How does SB 13 affect ADU construction in California?
SB 13 makes it faster, cheaper, and easier to build an ADU. It reduces or removes many local rules that used to block projects. You no longer have to wait months for permits or pay large fees, especially for smaller units. The law supports garage conversions, tiny homes, and other small living spaces.
What changes did SB 13 make to local zoning laws in California?
SB 13 limits how much control local governments have over ADUs. For example:
- They must allow one ADU and one Junior ADU on single-family lots.
- In short, SB 13 overrides local rules that are too strict.
- They can’t reject an ADU that meets basic size and setback standards.
They can’t require parking if your property is near public transportation.
Does SB 13 apply to all cities in California?
Yes, SB 13 applies statewide. All cities and counties in California must follow this law. However, some areas, like coastal cities, might have extra rules because of environmental protections, but they still have to follow the core parts of SB 13.
What are the key points of SB 13 California for property owners?
- Faster permit approvals (within 60 days).
- Lower or no fees for small ADUs.
- More flexibility with parking and setbacks.
- No owner-occupancy requirement (until at least 2025).
- Option to legalize unpermitted units built before 2020.
These points help property owners add more living space with fewer headaches.
Can I build an ADU under SB 13 in California?
Yes, if you’re a homeowner in California, you can build an ADU under SB 13 as long as your property meets basic state requirements. The law makes sure cities can’t stop you without a good reason. You may still need to follow some local guidelines, but the state law gives you strong protection.
How do I apply for an ADU permit under SB 13 in California?
You apply through your local city or county’s planning department. The process usually involves:
- Submitting a set of plans and documents for your ADU.
- Waiting up to 60 days for approval.
- Paying reduced fees (or none, if the unit is under 750 sq ft).
Your local building office will guide you, but SB 13 ensures they can’t delay or overcharge you.
Who can help me with an SB 13 compliant ADU in California?
You can get help from:
- ADU design firms or architects who know California laws.
- Contractors or builders who specialize in ADUs.
- Permit consultants who can handle paperwork for you.
Look for professionals with experience in SB 13 projects—they’ll know how to make the process smooth and legal.
How much does it cost to build an ADU under SB 13 in California?
The cost varies, but SB 13 helps lower the total price.
- A basic garage conversion may start around $80,000 to $120,000.
- A new detached ADU might cost $150,000 to $300,000, depending on size and location.
Thanks to SB 13, you won’t have to pay impact fees if your ADU is under 750 sq ft, and some cities also offer pre-approved plans to reduce costs.
Do I still need a permit to build an ADU with SB 13 in California?
Yes, you still need a permit, but the process is much easier now.
SB 13 says cities must approve permits within 60 days, and they can’t create unnecessary delays or reject your project for minor reasons.
Does SB 13 apply in Los Angeles, San Diego, San Jose, etc.?
Yes, SB 13 applies in every California city, including Los Angeles, San Diego, San Jose, and others. Local governments can’t block you from building an ADU if you follow the basic rules in the state law.
Are there special rules for SB 13 in coastal California cities?
Yes, some coastal cities have extra rules because of the California Coastal Act. That means you might need additional approvals or face stricter building limits. But even in these areas, cities must still follow the main parts of SB 13.
How does SB 13 work with other California housing laws like SB 9 or AB 68?
SB 13 works alongside other housing laws:
- AB 68 also supports ADUs and limits what cities can restrict.
- SB 9 allows lot splits and two units per lot in many areas.
When combined, these laws give homeowners more options to build, expand, or split properties.
Can local governments override SB 13 in California?
No, local governments can’t override SB 13. If a city tries to enforce rules that go against the law, the state can step in. The Department of Housing and Community Development (HCD) makes sure cities follow the rules.
What happens if a city does not comply with SB 13 in California?
If a city ignores or blocks SB 13, the state can take action. The HCD may send warnings or force the city to change its rules. In some cases, homeowners can appeal or file complaints to make sure their rights under SB 13 are respected.
Conclusion
SB 13 California brings clarity, speed, and affordability to ADU permitting. It eliminates many local barriers, requires approvals in 60 days, limits fees, and guarantees at least modest unit sizes and flexible parking rules. That’s transformative for California homeowners looking to maximize their property while supporting a more affordable housing future.
Whether you’re considering creating an ADU for rental income, housing a family member, or converting an existing structure, SB 13 California is your legal lever for building smarter, faster, and more affordably.