ADU Cost in Southern California: Complete 2026 Pricing Guide
- Maureen Leiderman
- Jan 29
- 14 min read
Updated: 3 hours ago
Building an ADU in California costs between $150,000 and $400,000+, depending on type, size, and location. Garage conversions are the most affordable option at $100,000-$175,000, while detached ADUs range from $200,000-$400,000+. In Southern California – Los Angeles, Orange, Riverside, and Ventura counties – costs run 10-20% higher than the state average due to labor rates, permit complexity, and material costs. This guide provides detailed pricing for every ADU type and county so you can budget accurately for your project.
How Much Does an ADU Cost in California?
An ADU in California costs $150,000 to $400,000+, depending on type, size, and location. Garage conversions run $100,000-$175,000. Attached ADUs (additions) cost $175,000-$300,000. Detached ADUs range from $200,000-$400,000+. In Southern California, expect to pay 10-20% more than Central or Northern California due to higher labor costs and stricter permitting requirements. Most ADUs fall between 400-1,200 square feet.
California ADU costs break down into four main categories:
Garage Conversion ($100,000-$175,000):
Converting an existing garage is the most cost-effective option because the structure already exists. Costs include foundation reinforcement, insulation, windows, plumbing, electrical, kitchen, bathroom, and finishes. In Southern California, garage conversions typically cost $120,000-$175,000 for a 400-600 square foot unit.
Junior ADU/JADU ($50,000-$100,000):
JADUs convert existing space within the main home (usually 150-500 square feet). They require a separate entrance, efficiency kitchen, and may share a bathroom with the main house. Lower costs reflect the minimal structural work required.
Attached ADU ($175,000-$300,000):
Building an addition to your existing home. Costs are similar to a home addition–you're essentially adding a small apartment. In Southern California, attached ADUs typically cost $200,000-$300,000 for a 500-800 square foot unit.
Detached ADU ($200,000-$400,000+):
A standalone structure built from the ground up. This is the most expensive option but offers the most privacy and flexibility. In Southern California, detached ADUs typically cost $250,000-$400,000+ for a 600-1,200 square foot unit.
Why California Costs More Than Other States:
California's Title 24 energy codes add $10,000-$20,000 in required efficiency features
Seismic engineering requirements add $3,000-$8,000
State and local permit fees range from $10,000-$25,000
Licensed contractor rates run 30-50% higher than many states
Material costs are elevated due to transportation and demand
Key Takeaways:
Garage conversion: $100,000-$175,000 (most affordable option)
Attached ADU: $175,000-$300,000 (addition to existing home)
Detached ADU: $200,000-$400,000+ (standalone new construction)
Southern California runs 10-20% above state averages
Plan for 12-18 months total (permits + construction)
How Much Does a Garage Conversion ADU Cost?
A garage conversion ADU in Southern California costs $100,000-$175,000, depending on size, condition of the existing garage, and finish level. A basic studio conversion (400 sq ft) with standard finishes runs $100,000-$130,000. A one-bedroom unit (500-600 sq ft) with mid-range finishes typically costs $140,000-$175,000. Garage conversions are the most cost-effective ADU option because the shell structure already exists.
Garage conversions offer excellent value because you're working with an existing structure. However, significant work is still required to convert a garage into a livable space.
Basic Garage Conversion ($100,000-$130,000):
Foundation reinforcement: $5,000-$12,000
Insulation and drywall: $8,000-$15,000
Windows and exterior door: $4,000-$8,000
Electrical (new panel, circuits, outlets): $8,000-$15,000
Plumbing (rough and finish): $12,000-$20,000
HVAC (mini-split): $4,000-$8,000
Kitchen (basic): $15,000-$25,000
Bathroom (basic): $10,000-$18,000
Flooring: $4,000-$8,000
Permits and plans: $10,000-$18,000
Labor and general conditions: $15,000-$25,000
Mid-Range Garage Conversion ($130,000-$160,000):
Everything above, plus:
Upgraded kitchen with quality cabinets and quartz countertops
Tile bathroom with glass shower enclosure
Upgraded flooring (LVP or tile throughout)
Better lighting fixtures
Washer/dryer hookups or stackable unit
Premium Garage Conversion ($160,000-$200,000+):
Custom or semi-custom cabinetry
Premium appliances
Luxury bathroom finishes
Hardwood or premium tile flooring
Smart home features
Outdoor living space integration
What Can Increase Garage Conversion Costs:
Raising the roof for ceiling height: $15,000-$30,000
Foundation issues or insufficient slab: $10,000-$25,000
Extensive utility runs from main house: $5,000-$15,000
Code-required parking replacement: $5,000-$20,000
Seismic retrofitting for older garages: $5,000-$15,000
Key Takeaways:
Basic studio conversion: $100,000-$130,000
Mid-range one-bedroom: $140,000-$175,000
Premium conversion: $160,000-$200,000+
Existing structure saves 30-40% compared to detached ADU
Foundation and roof condition significantly impact final cost
What Factors Affect ADU Construction Costs?
ADU construction costs are affected by five main factors: ADU type (garage conversion vs. detached), size (square footage), location (county and city), site conditions (utilities, access, slope), and finish level (standard vs. premium). In Southern California, permit complexity, lot conditions, and utility connection distances can swing costs by $30,000-$80,000 between similar projects. Understanding these factors helps you budget accurately.
1. ADU Type (Greatest Impact)
ADU Type | Cost Range | Why It Costs This Much |
JADU | $50,000-$100,000 | Uses existing space, minimal structural work |
Garage Conversion | $100,000-$175,000 | Shell exists, needs full interior buildout |
Attached ADU | $175,000-$300,000 | New construction tied to existing home |
Detached ADU | $200,000-$400,000+ | Completely new structure from foundation up |
2. Size (Linear Relationship)
Larger ADUs cost more, but cost per square foot often decreases:
400 sq ft ADU: $120,000-$180,000 ($300-$450/sf)
600 sq ft ADU: $150,000-$240,000 ($250-$400/sf)
800 sq ft ADU: $200,000-$320,000 ($250-$400/sf)
1,000 sq ft ADU: $250,000-$400,000 ($250-$400/sf)
1,200 sq ft ADU: $300,000-$480,000 ($250-$400/sf)
3. Location (County and City)
Costs vary significantly by location:
Los Angeles County: 15-25% above state average
Orange County: 10-20% above state average
Riverside County: At or slightly below state average
Ventura County: 5-15% above state average
Specific cities within each county can vary even more. Coastal cities (Santa Monica, Newport Beach) run significantly higher than inland areas.
4. Site Conditions (Often Underestimated)
Site-specific factors that increase costs:
Utility distance: Running water, sewer, and electrical from main house to detached ADU: $10,000-$40,000+ depending on distance
Slope: Hillside lots require retaining walls, special foundations: $20,000-$80,000+
Access: Difficult access (no side yard, crane required) adds $5,000-$20,000
Existing infrastructure: Electrical panel upgrade: $2,500-$6,000
Tree removal/protection: $2,000-$15,000 depending on species and location
Soil conditions: Poor soil requiring engineered foundation: $5,000-$20,000
5. Finish Level (Your Choice)
Finish Level | Kitchen | Bathroom | Flooring | Cost Impact |
Basic | Laminate, basic cabinets | Fiberglass tub, basic tile | LVP | Baseline |
Mid-Range | Quartz, semi-custom cabinets | Tile shower, quality fixtures | LVP or tile | +$15,000-$30,000 |
Premium | Stone, custom cabinets | Custom tile, frameless glass | Hardwood or premium tile | +$40,000-$80,000 |
Key Takeaways:
ADU type has the greatest impact on cost (can vary by $200,000+)
Larger ADUs cost more total but less per square foot
Location affects labor rates and permit costs significantly
Site conditions can add $20,000-$100,000 in unexpected costs
Finish level is where you have the most control
How Much Does an ADU Cost Per Square Foot?
ADU cost per square foot in Southern California ranges from $250-$500 depending on type and finish level. Garage conversions run $250-$350 per square foot. Attached ADUs cost $300-$450 per square foot. Detached ADUs range from $350-$500+ per square foot. These figures include all costs: design, permits, construction, and finishes. Smaller ADUs (under 500 sq ft) often cost more per square foot because fixed costs are spread over fewer square feet.
Cost per square foot is useful for rough budgeting, but it can be misleading. Here's how to use this metric correctly:
Cost Per Square Foot by ADU Type:
ADU Type | Cost/SF Range | What's Included |
Garage Conversion | $250-$350 | Interior buildout, all systems, finishes |
Attached ADU | $300-$450 | New construction attached to home |
Detached ADU | $350-$500+ | Complete new structure, utilities |
Prefab/Modular | $300-$400 | Factory-built, delivered, site work |
Why Cost Per Square Foot Varies:
Fixed Costs Don't Scale:
Every ADU needs a kitchen, bathroom, permits, and utility connections regardless of size. A 400 sq ft ADU might have $60,000 in fixed costs (kitchen, bath, permits, utilities). A 1,200 sq ft ADU might have $80,000 in fixed costs. This makes smaller ADUs cost more per square foot.
ADU Size | Fixed Costs | Variable Costs | Total | Cost/SF |
400 sf | $60,000 | $60,000 | $120,000 | $300/sf |
600 sf | $65,000 | $90,000 | $155,000 | $258/sf |
800 sf | $70,000 | $130,000 | $200,000 | $250/sf |
1,000 sf | $75,000 | $175,000 | $250,000 | $250/sf |
1,200 sf | $80,000 | $220,000 | $300,000 | $250/sf |
What "Cost Per Square Foot" Should Include:
A complete cost per square foot figure should include:
Architectural and engineering plans: $8,000-$20,000
Permits and fees: $10,000-$25,000
Site preparation: $5,000-$20,000
Foundation: $15,000-$40,000 (detached)
Framing and structure: $25,000-$60,000 (detached)
Roofing: $8,000-$20,000 (detached)
Plumbing: $15,000-$30,000
Electrical: $10,000-$25,000
HVAC: $5,000-$12,000
Insulation and drywall: $10,000-$25,000
Kitchen and bath: $25,000-$60,000
Flooring and finishes: $10,000-$30,000
Exterior and landscaping: $5,000-$20,000
Beware of Low Cost Per Square Foot Quotes:
If a contractor quotes significantly below $250/sf, ask what's excluded. Common exclusions that inflate the "true" cost:
Permits and plans
Utility connections
Site preparation
Landscaping
Appliances
Finish upgrades
Key Takeaways:
Garage conversion: $250-$350 per square foot
Attached ADU: $300-$450 per square foot
Detached ADU: $350-$500+ per square foot
Smaller ADUs cost more per square foot due to fixed costs
Always confirm what's included in cost per square foot quotes
ADU Cost Breakdown by Type
Garage Conversion ADU Cost Breakdown
Total Range: $100,000-$175,000
Cost Category | Percentage | Amount Range |
Plans & Permits | 10-12% | $10,000-$20,000 |
Foundation Work | 5-10% | $5,000-$15,000 |
Framing/Structure | 8-12% | $8,000-$18,000 |
Roofing (if needed) | 0-5% | $0-$8,000 |
Plumbing | 12-15% | $12,000-$25,000 |
Electrical | 10-12% | $10,000-$20,000 |
HVAC | 4-6% | $4,000-$10,000 |
Insulation/Drywall | 8-10% | $8,000-$15,000 |
Kitchen | 12-18% | $15,000-$30,000 |
Bathroom | 8-12% | $10,000-$20,000 |
Flooring | 4-6% | $4,000-$10,000 |
Windows/Doors | 4-6% | $4,000-$10,000 |
Finishes | 5-8% | $5,000-$12,000 |
Timeline: 3-5 months construction (after permits)
Attached ADU Cost Breakdown
Total Range: $175,000-$300,000
Cost Category | Percentage | Amount Range |
Plans & Permits | 8-10% | $15,000-$28,000 |
Foundation | 8-12% | $15,000-$35,000 |
Framing/Structure | 15-18% | $30,000-$50,000 |
Roofing | 5-7% | $10,000-$18,000 |
Plumbing | 10-12% | $18,000-$35,000 |
Electrical | 8-10% | $15,000-$28,000 |
HVAC | 4-5% | $8,000-$14,000 |
Insulation/Drywall | 8-10% | $15,000-$28,000 |
Kitchen | 10-14% | $20,000-$40,000 |
Bathroom | 6-10% | $12,000-$28,000 |
Flooring | 4-5% | $8,000-$14,000 |
Windows/Doors | 4-5% | $8,000-$14,000 |
Exterior/Siding | 4-6% | $8,000-$16,000 |
Finishes | 4-6% | $8,000-$16,000 |
Timeline: 4-7 months construction (after permits)
Detached ADU Cost Breakdown
Total Range: $200,000-$400,000+
Cost Category | Percentage | Amount Range |
Plans & Permits | 6-8% | $15,000-$30,000 |
Site Work | 5-8% | $12,000-$30,000 |
Foundation | 8-10% | $20,000-$40,000 |
Framing/Structure | 15-18% | $35,000-$70,000 |
Roofing | 5-6% | $12,000-$24,000 |
Plumbing | 8-10% | $20,000-$40,000 |
Electrical | 6-8% | $15,000-$32,000 |
HVAC | 3-5% | $8,000-$18,000 |
Insulation/Drywall | 6-8% | $15,000-$32,000 |
Kitchen | 8-12% | $20,000-$45,000 |
Bathroom | 5-8% | $12,000-$32,000 |
Flooring | 3-5% | $8,000-$18,000 |
Windows/Doors | 4-6% | $10,000-$24,000 |
Exterior/Siding | 5-7% | $12,000-$28,000 |
Utilities to Structure | 4-6% | $10,000-$24,000 |
Landscaping | 3-5% | $8,000-$18,000 |
Timeline: 5-8 months construction (after permits)
ADU Cost by County in Southern California
Los Angeles County ADU Cost
ADU Type | Cost Range | Notes |
Garage Conversion | $130,000-$200,000 | Highest in Westside, lower in Valley |
Attached ADU | $200,000-$350,000 | Complex permitting in many cities |
Detached ADU | $275,000-$450,000+ | Premium for coastal locations |
LA County Considerations:
Permit fees: $15,000-$25,000 (among highest in state)
Permit timeline: 8-16 weeks for approval
Many older homes require extensive utility upgrades
Parking requirements vary significantly by city
Some cities have streamlined ADU processes (LA City), others remain complex
Labor rates: $85-$175/hour depending on trade
Cities with Most ADU Activity: Los Angeles, Long Beach, Pasadena, Santa Monica, Glendale
Orange County ADU Cost
ADU Type | Cost Range | Notes |
Garage Conversion | $120,000-$185,000 | Competitive contractor market |
Attached ADU | $185,000-$320,000 | HOA restrictions in many communities |
Detached ADU | $250,000-$400,000 | Beach cities run 15-25% higher |
OC County Considerations:
Permit fees: $12,000-$20,000
Permit timeline: 6-12 weeks for approval
Many HOA communities have additional requirements
Newer housing stock often has adequate infrastructure
Strong contractor availability and competition
Labor rates: $80-$160/hour
Cities with Most ADU Activity: Anaheim, Santa Ana, Irvine, Huntington Beach, Fullerton
Riverside County ADU Cost
ADU Type | Cost Range | Notes |
Garage Conversion | $100,000-$160,000 | Best value in region |
Attached ADU | $160,000-$270,000 | Growing contractor pool |
Detached ADU | $220,000-$350,000 | Larger lots common |
Riverside County Considerations:
Permit fees: $8,000-$15,000 (lowest in Southern California)
Permit timeline: 4-8 weeks for approval (faster than coastal counties)
Larger lots make detached ADUs more feasible
Growing population driving demand for quality contractors
Labor rates: $65-$125/hour (10-20% below LA/OC)
DQB serves Riverside County extensively
Cities with Most ADU Activity: Riverside, Corona, Moreno Valley, Temecula, Murrieta
Ventura County ADU Cost
ADU Type | Cost Range | Notes |
Garage Conversion | $115,000-$175,000 | Mid-range for region |
Attached ADU | $175,000-$290,000 | Limited contractor pool |
Detached ADU | $240,000-$380,000 | Fire-resistant materials in some areas |
Ventura County Considerations:
Permit fees: $10,000-$18,000
Permit timeline: 6-10 weeks for approval
Fire-resistant construction required in many areas (WUI zones)
Smaller contractor market than LA/OC
Coastal cities (Ventura, Oxnard) command premium
Inland areas (Thousand Oaks, Simi Valley) more affordable
Labor rates: $75-$145/hour
Cities with Most ADU Activity: Ventura, Oxnard, Thousand Oaks, Simi Valley, Camarillo
ADU Return on Investment (ROI)
Rental Income Potential
ADU rental income in Southern California varies significantly by location:
County | Studio/1BR Rent | 2BR Rent | Annual Income |
Los Angeles | $1,800-$2,800 | $2,200-$3,500 | $21,600-$42,000 |
Orange | $1,700-$2,600 | $2,100-$3,200 | $20,400-$38,400 |
Riverside | $1,400-$2,000 | $1,700-$2,400 | $16,800-$28,800 |
Ventura | $1,600-$2,400 | $2,000-$3,000 | $19,200-$36,000 |
ROI Calculation Example
Riverside County Garage Conversion ADU:
Construction cost: $140,000
Monthly rent: $1,700
Annual gross income: $20,400
Expenses (taxes, insurance, maintenance): $3,000/year
Net annual income: $17,400
Simple ROI: 12.4% annually
Payback period: 8 years
Los Angeles County Detached ADU:
Construction cost: $320,000
Monthly rent: $2,800
Annual gross income: $33,600
Expenses (taxes, insurance, maintenance): $5,000/year
Net annual income: $28,600
Simple ROI: 8.9% annually
Payback period: 11.2 years
Property Value Increase
ADUs also increase your property value:
Immediate value add: Typically 50-70% of construction cost
Long-term value add: 80-100% of construction cost after rental income is established
Appraisal consideration: Lenders increasingly recognize ADU rental income
A $150,000 ADU might add $100,000-$150,000 to your property value, plus generate $18,000-$24,000 in annual rental income.
When ADU Investment Makes Sense
Strong ROI scenarios:
High-rent markets (LA, coastal OC, Ventura)
Family housing needs (aging parents, adult children)
Long-term ownership plans (5+ years)
Home-based business use (office, studio)
Property already has good site conditions
Weaker ROI scenarios:
Very high construction costs due to site challenges
Areas with rent control or tenant restrictions
Short-term ownership plans
Properties with infrastructure limitations
Already at maximum lot coverage
ADU Financing Options
How to Finance Your ADU
Most homeowners finance their ADU through home equity:
Home Equity Line of Credit (HELOC):
Interest rates: Prime + 0.5% to 2% (variable)
Loan amount: Up to 85% of home equity
Best for: Flexibility, interest-only payments during construction
Draw period: 10 years typically
Home Equity Loan:
Interest rates: 7-10% (fixed)
Loan amount: Up to 85% of home equity
Best for: Predictable fixed payments
Term: 10-20 years
Cash-Out Refinance:
Interest rates: Current mortgage rates
Loan amount: Up to 80% of home value
Best for: Low current interest rates, large equity
Replaces existing mortgage
Construction Loan:
Interest rates: Prime + 1-3% (variable)
Loan amount: Based on projected value
Best for: Limited current equity
Converts to permanent loan after construction
DQB's Financing Advantage
Dynamic Quality Builders offers a unique financing benefit: we cover your loan payments during construction.
Here's how it works:
You secure a HELOC or home equity loan for the ADU project
During the 3-6 month construction period, DQB covers your monthly loan payments (typically $1,000-$1,800/month)
These covered payments are added to the final project cost
You don't pay anything out of pocket until you receive the keys
Once complete, you begin making regular payments–often covered by rental income
Example:
ADU cost: $175,000
Monthly loan payment during construction: $1,400
Construction period: 5 months
DQB covers: $7,000 in payments
Final project cost: $182,000
Monthly payment after completion: ~$1,450
ADU rental income: $1,800/month
Net positive cash flow: $350/month from day one
Frequently Asked Questions
Q: How much does it cost to build an ADU in California in 2026?
A: Building an ADU in California in 2026 costs $150,000-$400,000 depending on type. Garage conversions run $100,000-$175,000. Attached ADUs cost $175,000-$300,000. Detached ADUs range from $200,000-$400,000+. Southern California prices run 10-20% above state averages. These costs include design, permits, construction, and basic finishes.
Q: What is the cheapest type of ADU to build?
A: The cheapest ADU type is a Junior ADU (JADU) at $50,000-$100,000, which converts existing space within your home. The cheapest standalone ADU is a garage conversion at $100,000-$175,000 in Southern California. Garage conversions cost less because the shell structure already exists–you're only building out the interior. Prefab ADUs can also be cost-effective at $100,000-$200,000 depending on size.
Q: How long does it take to build an ADU in California?
A: Total ADU timeline in California is typically 10-18 months from start to finish. This includes design and plans (1-2 months), permit approval (2-4 months in most cities, longer in LA), and construction (3-8 months depending on type). Garage conversions are fastest at 3-5 months of construction. Detached ADUs take 5-8 months. Streamlined permit processes in some cities can reduce total timeline by 2-3 months.
Q: Do I need a permit to build an ADU in California?
A: Yes, all ADUs in California require building permits. California law (AB 68, SB 13, AB 881) requires cities to approve ADU permits within 60 days if the application is complete. Permits ensure the ADU meets building codes for safety, energy efficiency, and habitability. Permit costs range from $10,000-$25,000 depending on your city and ADU type.
Q: Can I build an ADU on any property in California?
A: California law allows ADUs on any property zoned for residential use (single-family or multifamily). However, your lot must have space for the ADU while meeting setback requirements (typically 4 feet from rear and side property lines for ADUs under 16 feet tall). Some HOAs have additional rules, though they cannot prohibit ADUs outright. Properties in fire zones, flood zones, or with historic designations may have additional requirements.
Q: How much does it cost to convert a garage to an ADU?
A: Garage conversion ADU costs in Southern California range from $100,000-$175,000. Basic studio conversions (400 sq ft) run $100,000-$130,000. One-bedroom units with mid-range finishes cost $140,000-$175,000. Factors that increase cost include raising the roof for ceiling height (+$15,000-$30,000), foundation issues (+$10,000-$25,000), and extensive utility runs (+$5,000-$15,000).
Q: What is the most expensive part of building an ADU?
A: For detached ADUs, the foundation and framing represent the largest costs at 23-28% of the total budget ($40,000-$100,000). For garage conversions, the kitchen and bathroom are typically the most expensive at 20-30% ($25,000-$50,000 combined). Permits and plans also represent a significant fixed cost at $10,000-$25,000 regardless of ADU size.
Q: Can I live in my ADU while renting out my main house?
A: Yes, California law allows you to live in your ADU while renting the main house. There's no requirement that the property owner live on-site. This strategy–called "house hacking"–can maximize rental income. Your ADU must meet all habitability requirements (full kitchen, bathroom, separate entrance) to be legally occupied.
Q: Do ADUs increase property value?
A: Yes, ADUs typically increase property value by 50-100% of construction cost. A $150,000 ADU might add $100,000-$150,000 to your property value. The exact increase depends on location, ADU quality, and rental income potential. In high-rent markets like Los Angeles, ADUs can add significant value because buyers factor in the income potential.
Q: How much rent can I charge for an ADU in Southern California?
A: ADU rents in Southern California range from $1,400-$3,500 depending on location and size. Riverside County: $1,400-$2,400/month. Ventura County: $1,600-$3,000/month. Orange County: $1,700-$3,200/month. Los Angeles County: $1,800-$3,500/month. Studios and one-bedrooms are most common, with larger two-bedroom ADUs commanding premium rents.
Q: Is it cheaper to build a prefab or stick-built ADU?
A: Prefab and stick-built ADUs cost roughly the same in Southern California: $200,000-$400,000 for detached units. Prefab ADUs can be faster (3-4 months on-site vs 5-8 months) but require significant site work that adds cost. Prefab works best on flat lots with good access. Stick-built offers more customization and works on challenging sites. DQB builds custom stick-built ADUs that can be tailored to your exact specifications.
Q: What size ADU can I build on my property?
A: California law allows ADUs up to 850 square feet for studios and one-bedrooms, or 1,000 square feet for two-or-more-bedroom units. However, if you have adequate lot coverage, many cities allow up to 1,200 square feet. Junior ADUs (JADUs) are limited to 500 square feet and must be within the existing home footprint. Detached ADUs must be at least 4 feet from property lines and 10 feet from the main house.
Q: Do I need to provide parking for my ADU?
A: California law eliminates parking requirements for ADUs within half a mile of public transit, in historic districts, in existing structures (like garage conversions), or when on-street parking permits aren't required. Most ADUs in Southern California qualify for these exemptions. If parking is required, one space per bedroom is typical–though many cities don't require any additional parking.
Q: How do I finance an ADU with no money down?
A: "No money down" ADU financing is possible through home equity. If your home has 40-50% equity, you can borrow the full ADU cost through a HELOC or home equity loan. DQB's financing model covers your loan payments during construction, meaning you pay nothing out of pocket until the ADU is complete. At that point, rental income often covers the monthly payment.
Q: What's the ROI on an ADU in California?
A: ADU ROI in California ranges from 8-15% annually, depending on construction cost and rental income. In Riverside County, a $140,000 garage conversion renting for $1,700/month generates about 12% ROI. In Los Angeles, a $320,000 detached ADU renting for $2,800/month generates about 9% ROI. Payback periods range from 7-12 years, faster than most real estate investments.
Q: Can I use my ADU for Airbnb or short-term rental?
A: Short-term rental rules vary by city. Many California cities restrict or ban short-term rentals of ADUs. Los Angeles limits STRs to your primary residence. Some cities allow STRs with permits and occupancy taxes. Before planning to Airbnb your ADU, check your city's specific regulations. Long-term rental is permitted everywhere and often provides more stable income.
Next Steps: Get Your ADU Cost Estimate
Ready to build an ADU? Here's how Dynamic Quality Builders makes the process simple:
Step 1: Free Consultation
Contact us for a no-obligation assessment. We'll:
Visit your property to evaluate site conditions
Discuss your goals (rental income, family housing, home office)
Review your lot for ADU feasibility
Provide preliminary cost ranges based on your situation
Step 2: Design & Budget Development
Once you decide to move forward:
Architect creates plans tailored to your site and budget
We provide detailed, line-item pricing
Explore financing options and payment coverage program
Help you understand ROI potential
Step 3: Permit Submittal
We handle all permitting:
Submit complete plans to your city
Respond to plan check comments
Schedule and pass all inspections
Typical timeline: 2-4 months for approval
Step 4: Construction
Our experienced crews build your ADU:
Clear communication and progress updates
Quality workmanship with attention to detail
Clean job sites and respectful of your property
On-time completion per contract
Step 5: Keys in Hand
Upon completion:
Final walkthrough and punch list
Provide warranty documentation
Help you prepare for rental or occupancy
Begin enjoying your investment
Ready to Get Started?
Schedule your property assessment today. We'll provide accurate pricing for your specific situation. No obligation.
Call Us Today: +1 (562) 552-2934
Serving Southern California: Los Angeles County, Orange County, Riverside County, Ventura County
Sources:
California HCD “Accessory Dwelling Unit Handbook” PDF (state rules, size, parking, impact‑fee framework).
Angi “How Much Does an ADU Cost to Build? [2026 Data]” – national ADU cost ranges
HomeAdvisor “What Is the Average Cost to Build an In‑Law Suite? [2025 Data]” – good proxy for attached/detached ADU‑type projects.
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