How does SB-9 work in San Diego?

Patricia Anderson
October 19, 2025 at 10:33 PM
SB-9 (Lot Splits) San Diego, CA
Hello everyone,

I'm a homeowner in San Diego trying to navigate the complexities of SB-9, particularly concerning lot splits. I own a mid-sized property in the North Park neighborhood, measuring around 6,500 square feet. I'm considering splitting my lot to potentially create an additional unit, but I'm finding it difficult to piece all the information together.

From what I've gathered, SB-9 allows for lot splits, but I'm unsure about the specific requirements for my area. Does anyone know if San Diego has specific zoning regulations that might affect my ability to split the lot? I've heard something about maintaining a certain percentage for the main residence, but the details are fuzzy.

Additionally, my budget is relatively tight, and I want to understand the financial implications better. Are there any hidden fees, such as permit costs or infrastructure upgrades, that I should be aware of? Any advice on budgeting for this process would be greatly appreciated.

Finally, I'm concerned about the impact on the neighborhood. Are there any community considerations or local opposition that could affect my project? I want to ensure I'm respectful of my neighbors and comply with all local guidelines.

Thanks for any insights or experiences you can share! It's a bit overwhelming, and getting accurate, detailed advice would really help me move forward.

1 Answer

Sarah Mitchell
October 19, 2025 at 10:47 AM
Hello,

Navigating SB-9 can indeed feel overwhelming, especially given the intricacies involved in lot splits and additional unit development in cities like San Diego. Let’s break down your questions step-by-step to help clarify your situation and guide you through this process.

### Understanding SB-9 in San Diego

**SB-9 Overview:** Enacted in January 2022, SB-9 allows homeowners to split their single-family residential lots and build up to two units on each lot. This effectively means that you could potentially have up to four units on your original parcel — two on each split lot.

**Lot Split Requirements:**
1. **Lot Size:** Your current lot, at 6,500 square feet, is eligible for a lot split under SB-9, as it exceeds the minimum requirement of 2,400 square feet per new lot. Each new lot must be at least 1,200 square feet.
2. **Owner Occupancy:** You must sign an affidavit stating that you intend to occupy one of the housing units as your principal residence for a minimum of three years from the date of the lot split.
3. **Zoning and Restrictions:** SB-9 overrides local zoning to a degree but San Diego may still have specific ordinances regarding setbacks and height restrictions. Usually, you can expect setbacks of 4 feet from the side and rear, but confirm with the local planning department.

### Financial Considerations

**Permitting and Fees:**
- **Permit Costs:** In San Diego, permits for lot splits and construction can range from $5,000 to $15,000 depending on the complexity of your project.
- **Impact Fees:** While SB-9 may exempt you from certain impact fees for units under 750 square feet, larger units could incur fees ranging from $10,000 to $15,000 each.
- **Infrastructure Upgrades:** Depending on your existing utilities, you might need to upgrade water, sewer, or electrical lines, which could add $10,000 to $30,000 to your budget.

**Budgeting Tips:**
- **Contingency Fund:** Allocate an additional 10-20% of your budget to cover unexpected costs.
- **Financing Options:** Consider home equity loans or lines of credit to finance the project. Some local banks offer specific programs for ADU projects.

### Community and Neighborhood Impact

**Neighborhood Considerations:**
- **Community Feedback:** Engage with your neighbors early in the process. Hosting a small neighborhood meeting to discuss your plans can help mitigate opposition.
- **Local Opposition:** Be aware that neighborhood associations may have informal power. Keeping them informed and involved can prevent conflicts.

**Compliance and Respect:**
- Ensure compliance with all local noise ordinances and construction times to minimize disturbances.

### Steps to Move Forward

1. **Consult with a Local Architect or Planner:** They can help assess your property, provide design options, and navigate the permitting process.
2. **Contact San Diego’s Planning Department:** Confirm specific local requirements and get a clearer picture of any additional zoning laws that apply.
3. **Hire a Qualified Contractor:** Choose someone with experience in ADU projects under SB-9 to avoid common pitfalls.
4. **Check for Historical Designation:** Ensure your property isn’t in a historic district, which could impose additional regulations.
5. **Secure Financing:** Finalize your budget and financing options before starting the project to ensure you can cover all costs.

### Additional Resources

- **San Diego Planning Department:** Check their website for guides on SB-9 and ADU development.
- **California Department of Housing and Community Development:** Offers resources and updates on state housing laws.
- **Local Workshops or Seminars:** San Diego sometimes hosts workshops on ADU and SB-9 development that can provide valuable insights.

### Final Tips

- **Be Patient:** The entire process, from planning to completion, can take 12-18 months, so plan accordingly.
- **Thorough Documentation:** Keep meticulous records of all communications and documents related to the project.

By carefully considering these aspects and following the steps outlined, you can successfully navigate the SB-9 process in San Diego. Best of luck with your project, and feel free to reach out if you have further questions!

Warm regards,

[Your Name]
ADU Consultant and San Diego Expert
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Types of ADUs in San Diego, CA

Understanding the different types of Accessory Dwelling Units can help you choose the best option for your property and needs.

Detached ADU

A separate, standalone structure built on your property. Offers maximum privacy and flexibility for tenants.

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Attached ADU

An addition to your existing home with a separate entrance. Cost-effective option with shared utilities.

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Garage Conversion

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JADU

Junior ADU created within the existing home. Maximum 500 sq ft with efficiency kitchen and shared utilities.

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Upper Floor ADU

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Basement ADU

Convert basement or lower level into living space. Great option for properties with existing below-grade areas.

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ADU Cost Guide for San Diego, CA

Understanding ADU costs helps you budget effectively and make informed decisions about your project. Costs vary based on size, complexity, and local factors.

ADU Type Size Range Cost Range Timeline Best For
Garage Conversion 400-800 sq ft $80K - $150K 3-6 months Budget-conscious homeowners
JADU Up to 500 sq ft $50K - $100K 2-4 months Family use, minimal disruption
Attached ADU 600-1,000 sq ft $120K - $200K 4-8 months Shared utilities, family proximity
Detached ADU 600-1,200 sq ft $150K - $300K 6-12 months Maximum rental income
Two-Story ADU 800-1,500 sq ft $200K - $400K 8-15 months Maximizing property value
Cost Factors to Consider
  • Site Preparation: $5K - $25K
  • Permits & Fees: $3K - $15K
  • Utility Connections: $5K - $20K
  • Finish Level: $10K - $50K variance
  • Landscaping: $2K - $10K
Potential ROI
  • Rental Income: $1,500 - $4,000/month
  • Property Value Increase: 20-30%
  • Payback Period: 8-15 years
  • Tax Benefits: Depreciation allowances
  • Equity Growth: Long-term appreciation
Get Your Personalized Cost Estimate

These are general ranges. Your actual costs may vary based on specific site conditions, design choices, and local market factors in San Diego.

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Why Build an ADU in San Diego?

Financial Benefits
Rental Income: Generate $18,000-$48,000 annually
Property Value: Increase home value by 20-30%
Tax Benefits: Depreciation and expense deductions
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Lifestyle Benefits
Multigenerational Living: Keep family close while maintaining privacy
Home Office: Create dedicated workspace or studio
Guest Space: Comfortable accommodations for visitors
Sustainability: Increase housing density efficiently

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Cascade ADU Floor Plan - 2 Bedroom, 2 Bathroom
2 Bed 2 Bath 1,200 sq ft
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Summit ADU Floor Plan - 2 Bedroom, 2 Bathroom
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Crestline ADU Floor Plan - 3 Bedroom, 2 Bathroom
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Types of ADUs in San Diego, CA

Understanding the different types of Accessory Dwelling Units available in San Diego, CA can help you choose the best option for your property and budget.

Detached ADU

A standalone structure separate from the main house. Offers maximum privacy and flexibility.

  • Maximum privacy
  • Flexible design options
  • Higher rental income potential
Garage Conversion

Converting an existing garage into a living space. Most cost-effective option.

  • Lower construction costs
  • Faster permitting process
  • Existing utilities nearby
Attached ADU

An addition to the existing house with separate entrance. Balances cost and privacy.

  • Shared utilities
  • Moderate construction costs
  • Easy maintenance access
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ADU Cost Guide for San Diego, CA

Understanding ADU costs helps you budget effectively and make informed decisions about your project in San Diego, CA.

ADU Type Size Range Cost Range Cost per Sq Ft Timeline
Garage Conversion 400-800 sq ft $80,000 - $150,000 $200 - $250 3-6 months
Attached ADU 500-1,200 sq ft $150,000 - $300,000 $250 - $350 6-9 months
Detached ADU 600-1,200 sq ft $200,000 - $400,000 $300 - $450 8-12 months
Prefab ADU 400-1,000 sq ft $120,000 - $250,000 $250 - $350 4-8 months
JADU (Junior ADU) Up to 500 sq ft $50,000 - $120,000 $150 - $300 2-4 months
Cost Factors to Consider:
  • Site preparation and utilities
  • Permits and plan review fees
  • Foundation and structural work
  • Finishes and appliances
  • Landscaping and driveway
Ways to Save Money:
  • Choose garage conversion over new build
  • Use prefab or modular construction
  • Keep design simple and efficient
  • Bundle with main house renovations
  • Work with experienced ADU builders
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Complete Guide to SB-9 (Lot Splits) ADUs in San Diego, CA

Understanding SB-9 (Lot Splits) for ADU Projects

ADU development in San Diego, CA involves numerous considerations specific to sb-9 (lot splits). Understanding local requirements, best practices, and potential challenges helps ensure project success.

Each ADU project is unique, with specific circumstances that influence design, permitting, and construction decisions. Professional guidance helps navigate these complexities and achieve optimal outcomes.

The GatherADU team has extensive experience with sb-9 (lot splits) aspects of ADU development and can provide expert assistance throughout your project.

SB-9 (Lot Splits) Requirements in San Diego, CA

Local regulations in San Diego, CA have specific requirements that affect ADU development. Understanding these local nuances is crucial for project success and compliance.

San Diego has 25 ADU-related questions in our database, indicating active development interest in your area. This local activity suggests growing expertise among contractors, architects, and city officials familiar with ADU projects.

Common considerations for San Diego include local architectural standards, historical district requirements if applicable, utility connection procedures, and neighborhood-specific zoning overlays that may affect your project.

Expert Insights on SB-9 (Lot Splits)

The GatherADU team has helped hundreds of homeowners navigate sb-9 (lot splits) challenges successfully. Our experience reveals common patterns, effective strategies, and potential pitfalls to avoid.

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ADU Development Checklist for San Diego, CA

Use this comprehensive checklist to ensure you don't miss important steps in your ADU development process.

Planning Phase
  • Define project goals and budget
  • Research local zoning requirements
  • Evaluate site conditions and constraints
  • Consult with ADU experts
  • Develop preliminary design concepts
Pre-Construction
  • Finalize architectural plans
  • Submit permit applications
  • Select qualified contractors
  • Secure financing if needed
  • Schedule utility connections
Construction Phase
  • Site preparation and excavation
  • Foundation and framing work
  • Rough-in electrical and plumbing
  • Insulation and drywall installation
  • Interior and exterior finishes
Completion
  • Final inspections and approvals
  • Certificate of occupancy
  • Utility meter installation
  • Final walkthrough and cleanup
  • Property insurance updates
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Related Topics
SB-9 (Lot Splits) San Diego ADU Planning Permits
San Diego, CA

This question is specific to San Diego, CA

Local regulations may vary by jurisdiction. Always verify with your local planning department.