How much does it cost to build an ADU in San Francisco?
I've heard costs can vary wildly, but I'm trying to get a realistic budget together. What should I expect for:
- Permits and fees
- Construction costs per sq ft
- Utility connections
- Any hidden costs I might not be thinking of?
I'm planning to rent it out long-term to help with my mortgage. Any insights would be really helpful!
2 Answers
**Permits & Fees:** $15,000-20,000 (including city fees, utility connections, and various inspections)
**Construction:** $300-400 per sq ft for a basic finish, $400-600 for higher-end
**Utility connections:** $8,000-12,000 (electrical, plumbing, gas)
For a 700 sq ft unit, I ended up spending about $280,000 total including permits. Some tips:
- Budget 20% extra for unexpected costs
- Pre-fab units can save money but still need permits
- Consider the long-term rental income - mine cash flows positive at $3,200/month rent
The permit process took about 5 months, construction another 8 months. Worth it for the rental income though!
One thing to watch out for - if your lot slopes or has any soil issues, you might need additional foundation work which can add $20-30K easily.
Also, if you're planning to rent it out, make sure to factor in:
- Property tax increase (around $3K/year for me)
- Insurance increase
- Maintenance reserves
Even with those costs, at current SF rents ($3K+ for a 1BR ADU), the ROI is still solid. Just took me longer than expected - nearly 14 months total from permit to move-in ready.
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Get Instant QuoteTypes of ADUs in San Francisco, 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.
- Complete privacy
- Custom design options
- Higher rental income potential
Attached ADU
An addition to your existing home with a separate entrance. Cost-effective option with shared utilities.
- Lower construction costs
- Shared utility connections
- Family-friendly proximity
Garage Conversion
Convert existing garage space into a livable unit. Most cost-effective ADU option with fastest approval.
- Lowest construction cost
- Faster permitting
- Uses existing structure
JADU
Junior ADU created within the existing home. Maximum 500 sq ft with efficiency kitchen and shared utilities.
- Minimal construction
- No parking requirement
- Perfect for family use
Upper Floor ADU
Add a second story or convert existing upper floor space. Maximizes property value and rental potential.
- Premium rental rates
- Enhanced privacy
- Great city views
Basement ADU
Convert basement or lower level into living space. Great option for properties with existing below-grade areas.
- Uses existing space
- Natural temperature control
- Sound isolation
ADU Cost Guide for San Francisco, 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 Francisco.
Get Detailed QuoteWhy Build an ADU in San Francisco?
Financial Benefits
Lifestyle Benefits
Popular ADU Floor Plans
Explore our most popular ADU designs that work well in San Francisco, CA. These professionally designed floor plans optimize space and functionality while meeting local building requirements.
The Cascade
Spacious 2-bedroom design perfect for families. Features open living area, full kitchen, and two full bathrooms with optimal privacy.
Master suite
Laundry room
The Summit
Efficient 2-bedroom layout maximizing every square foot. Great for narrow lots with smart storage solutions throughout.
Pantry storage
Two full baths
The Brookside
Luxurious 2-bedroom design with premium features. Includes master suite, guest bedroom, and spacious living areas.
Walk-in closets
Full kitchen island
The Sequoia
Unique 3-bedroom configuration perfect for larger families. Features dual bathrooms and smart space utilization.
Laundry room
Multiple closets
The Crestline
Premium 3-bedroom layout with maximum comfort. Features spacious bedrooms, walk-in closets, and luxury finishes.
Pantry space
Open concept
Ready to Explore More ADU Designs?
Browse our complete collection of ADU floor plans with detailed specifications, 3D renderings, and customization options.
View All Floor PlansComplete Guide to Cost & Budget ADUs in San Francisco, CA
Understanding Cost & Budget for ADU Projects
Understanding ADU costs and budgeting effectively is essential for project planning in San Francisco, CA. Construction costs vary based on size, complexity, site conditions, and local market factors.
Budget considerations include design fees, permit costs, site preparation, construction materials, labor costs, utility connections, and contingency reserves. Hidden costs often arise during construction, so proper planning and realistic budgeting are crucial.
Financial planning should also consider potential return on investment through rental income or increased property value. Professional cost estimation helps ensure your project remains financially viable throughout the construction process.
Cost & Budget Requirements in San Francisco, CA
Local regulations in San Francisco, CA have specific requirements that affect ADU development. Understanding these local nuances is crucial for project success and compliance.
San Francisco has 1 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 Francisco 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 Cost & Budget
The GatherADU team has helped hundreds of homeowners navigate cost & budget challenges successfully. Our experience reveals common patterns, effective strategies, and potential pitfalls to avoid.
Professional consultation early in your project can prevent costly mistakes and delays. We've seen how proper planning in the cost & budget phase saves both time and money throughout the entire ADU development process.
Our database contains 9 questions related to Cost & Budget, with 12 expert answers providing comprehensive guidance for homeowners facing similar challenges.
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More Cost & Budget Questions & Answers
Explore additional cost & budget questions from our community to gain deeper insights into ADU development challenges and solutions.
Can I build an ADU in Burbank with a shared wall less than 5 feet long?
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June 22, 2025Can I avoid impact fees for my 700-square-foot ADU in LA, or do they still apply for smaller units?
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May 17, 2025Can I build a 900-square-foot ADU in Glendale without paying development impact fees?
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May 15, 2025My Glendale multifamily building is multi-story. Can my detached ADUs be 18 feet tall?
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April 25, 2025My LA Ordinance ADU is 900 square feet. Do I need to pay school fees, and how are they calculated?
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April 24, 2025My Glendale ADU will be 600 square feet. Do I need to pay school fees?
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April 13, 2025Related ADU Questions
These questions share similar topics or locations and may provide additional insights for your ADU project.
Can I build an ADU in Burbank with a shared wall less than 5 feet long?
Can I avoid impact fees for my 700-square-foot ADU in LA, or do they still apply for smaller units?
Can I combine a detached State ADU with an attached Ordinance ADU on my LA single-family lot, and what’s the max square footage for each?
How do I figure out my single-family home’s square footage for ADU impact fees over 750 square feet in LA? Can I just use the County Tax Assessor’s records?
Can I build a 900-square-foot ADU in Glendale without paying development impact fees?
ADU Development Checklist for San Francisco, 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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San Francisco, CA
This question is specific to San Francisco, CA
Local regulations may vary by jurisdiction. Always verify with your local planning department.