ADU Construction San Diego | $80K-$350K | Garage Conversions & New Builds

8 min read RemodelSD San Diego, CA
San Diego ADU Experts | (858) 434-7166 | CSLB #1054602 | California ADU Law Specialists

San Diego ADU Construction

Build passive income and increase your property value with an Accessory Dwelling Unit. Whether it's a garage conversion, backyard cottage, or luxury guesthouse, we handle design, permits, and construction from start to rental-ready.

Garage Conversions from $80K New Construction from $150K Permits in 60 Days (State Law) Financing Available
Calculate ADU Cost Free Site Assessment
San Diego ADU Investment Returns
Monthly Rent Range$1,500-$3,500
Annual Rental Income$18K-$42K
Property Value Increase+$150K-$300K
Typical ROI Period4-7 Years

Why Build an ADU in San Diego?

Free Garage Conversion Cost Calculator Get an instant estimate for your San Diego project

An Accessory Dwelling Unit (ADU) is one of the smartest investments you can make in San Diego's competitive real estate market. With rental demand at historic highs and California's streamlined ADU laws making permitting faster than ever, homeowners are adding ADUs to generate passive income, house family members, or increase property value.

San Diego is particularly favorable for ADU investment. Strong rental demand means units rent quickly at premium rates - a well-designed 600 sq ft ADU can command $2,000-$2,800/month in most neighborhoods, with coastal areas fetching even more. Meanwhile, California's pro-ADU legislation has removed many traditional barriers: parking requirements are largely eliminated, setback minimums are reduced, and cities must approve compliant applications within 60 days.

ADU Types We Build

We specialize in all types of ADUs permitted under California law, each with its own advantages:

Garage Conversion ADUs ($80K-$150K)

Converting an existing 2-car garage is the most cost-effective path to ADU ownership. Since the structure already exists, you save on foundation and framing costs. We reinforce the structure as needed, add insulation, install bathroom and kitchen plumbing, upgrade electrical, and finish the interior to create a comfortable living space. Most garage conversions yield 400-600 sq ft units and take 3-4 months to complete.

Detached Backyard ADUs ($150K-$250K)

A new detached ADU in your backyard offers maximum flexibility in design and layout. California law allows up to 1,200 sq ft for detached ADUs. Popular configurations include studios (400-500 sq ft), one-bedrooms (500-700 sq ft), and two-bedrooms (700-1,000 sq ft). These units command the highest rents because tenants value the privacy of a separate structure.

Attached ADUs ($100K-$180K)

If you have unused space attached to your home - an oversized bonus room, unused basement, or covered patio - an attached ADU may be your most efficient option. We create a separate entrance, add a kitchen and bathroom, and soundproof the shared wall. Attached ADUs are typically 400-800 sq ft.

Junior ADUs (JADUs) ($50K-$100K)

A Junior ADU is created entirely within your existing home's footprint - often a converted bedroom with an added efficiency kitchen and its own entrance. JADUs are limited to 500 sq ft and can share a bathroom with the main house. The major advantage: you can build both a JADU AND a standard ADU on most single-family lots, potentially creating two income streams.

California ADU Law Highlights (2024-2026)

  • 60-Day Permit Approval: Cities must approve compliant ADU applications within 60 days (AB 68)
  • No Parking Required: Within 1/2 mile of transit, historic districts, or when converting existing structures
  • Reduced Setbacks: Only 4 feet required from side and rear property lines
  • Size Allowance: Up to 1,200 sq ft for detached ADUs regardless of lot size
  • Multiple ADUs: Single-family lots can have 1 ADU + 1 JADU; multi-family can have more
  • No Owner-Occupancy (New!): AB 1033 removed owner-occupancy requirements for many ADUs

ADU Types & Costs (San Diego 2026)

Investment-grade construction with transparent pricing

🚗
Garage Conversion
$80K-$150K
  • Use existing structure
  • 400-600 sq ft typical
  • 3-4 month construction
  • No parking replacement needed
  • Fastest permit approval
  • Expected rent: $1,500-$2,200/mo
Calculate Cost
🏡
Detached ADU
$150K-$250K
  • New backyard construction
  • Up to 1,200 sq ft
  • 5-7 month construction
  • Full kitchen & bath
  • Maximum rental value
  • Expected rent: $2,000-$3,500/mo
Calculate Cost
Luxury ADU
$250K-$350K+
  • Premium finishes throughout
  • 800-1,200 sq ft
  • Custom architecture
  • High-end appliances
  • Smart home features
  • Expected rent: $3,000-$4,500/mo
Calculate Cost

ADU Construction Timeline

From first call to rental-ready in 6-12 months

1

Site Assessment

Free evaluation of your property. We determine ADU feasibility, size options, utility access, and provide preliminary pricing. (1-2 weeks)

2

Design & Permits

Architectural plans, engineering, and permit submission to City of San Diego. State law requires approval within 60 days. (60-90 days)

3

Construction

Foundation, framing, MEP, finishes. Regular progress updates and city inspections. Garage: 3-4 mo. New build: 5-7 mo.

4

Final Inspection

City final inspection, utility connections verified, Certificate of Occupancy issued. Your ADU is legally rental-ready!

What to Expect: Month-by-Month ADU Timeline

Building an ADU is a significant project. Here's what happens each step of the way for a typical detached ADU:

Months 1-2: Planning & Design

After your free site assessment, we'll help you choose the right ADU size and layout for your goals. Our architects prepare detailed plans including floor plans, elevations, and 3D renderings. You'll select finishes, cabinets, and fixtures. We handle soil reports, structural engineering, and Title 24 energy calculations. Once plans are complete, we submit to the City of San Diego for permit review.

Month 3: Permit Review

California law requires cities to approve compliant ADU applications within 60 days. We monitor your application, respond to any plan check comments, and coordinate with city staff. Most San Diego ADU permits are approved in 45-60 days. During this time, we finalize your construction schedule and material orders.

Month 4: Site Preparation

Once permitted, construction begins with site preparation. For detached ADUs: grading, utility trenching (sewer, water, electrical, gas), and foundation work. For garage conversions: structural reinforcement, floor leveling, and rough openings for windows/doors. All underground utilities must be inspected before we pour the foundation.

Months 5-6: Framing & Rough-Ins

This is when your ADU really takes shape. Framing goes up, roofing is installed, and windows and doors are set. Electrical, plumbing, and HVAC rough-ins follow, with inspections at each stage. Insulation is installed per Title 24 requirements. By the end of this phase, you can walk through and see the final layout.

Months 7-8: Finishes & Completion

Drywall installation, texturing, and painting. Flooring, cabinets, and countertops. Bathroom and kitchen fixtures. Appliance installation. Final electrical and plumbing trim. Exterior finishes including siding, paint, and landscaping repair. Final city inspection and Certificate of Occupancy!

Note: Garage conversions follow a faster timeline (3-4 months construction). Luxury ADUs with custom features may take 8-10 months. We provide a detailed schedule specific to your project before work begins.

What Our ADU Clients Say

Real reviews from San Diego homeowners who built with us

★★★★★

"Built a beautiful 600 sq ft detached ADU in our Clairemont backyard. Now renting for $2,200/month! The team handled everything from permits to final inspection. Worth every penny of our investment."

Mark & Susan H.

Clairemont

★★★★★

"Converted our 2-car garage to a studio ADU for my mother-in-law. She loves having her own space but being close to family. The whole process took 4 months and they kept us informed throughout."

The Garcia Family

National City

★★★★★

"As a real estate investor, I've worked with several ADU builders. RemodelSD is the best - they know the San Diego permitting process inside and out and deliver quality construction on time."

Jennifer L.

Real Estate Investor

San Diego ADU FAQs

Common questions about California ADU construction

How much does an ADU cost in San Diego?

ADU costs range from $80,000-$150,000 for garage conversions, $150,000-$250,000 for standard detached ADUs, and $250,000-$350,000+ for luxury custom units. Price per square foot is typically $200-$400 depending on finishes, site conditions, and utility connections. Junior ADUs (JADUs) within existing structures cost $50,000-$100,000.

How long does it take to build an ADU in San Diego?

Total timeline from first consultation to rental-ready is 6-12 months. Design and permitting takes 2-4 months (state law requires permit approval within 60 days). Construction takes 3-4 months for garage conversions or 5-7 months for new detached construction.

How much rent can I charge for an ADU in San Diego?

ADU rent in San Diego ranges from $1,500-$3,500/month depending on size, location, and finishes. Coastal areas (La Jolla, Pacific Beach, Del Mar) command $2,500-$4,500/month. A well-designed 600 sq ft ADU can generate $24,000-$42,000/year in rental income.

Can I build an ADU on my property?

Most San Diego residential properties can have at least one ADU. Under California law, single-family lots can add both an ADU (up to 1,200 sq ft) AND a Junior ADU (up to 500 sq ft). Multi-family properties can add multiple ADUs. Setbacks are minimal (4 ft side/rear). We provide free site assessments to determine your options.

Do I need parking for an ADU?

No parking is required in most cases! California law eliminated parking requirements for ADUs within 1/2 mile of public transit (which covers most of San Diego), in historic districts, or when converting existing structures like garages. Even the parking replaced by a converted garage does not need to be recreated.

Will an ADU increase my property taxes?

Yes, but only on the new construction value - not your entire property (thanks to Proposition 13). For a $200,000 ADU, expect approximately $2,000-$2,500/year in additional property taxes. This is typically far less than the rental income generated.

Can I use my ADU for Airbnb?

San Diego has specific short-term rental regulations. In most residential zones, you can only do short-term rentals if you live on the property (either in the main house or ADU). Some zones prohibit STRs entirely. Long-term rentals (30+ days) are always permitted. We recommend checking current regulations for your specific zone.

How does ADU financing work?

Popular ADU financing options include: home equity loans (HELOCs), cash-out refinancing, construction loans, and ADU-specific lending products. Some programs offer special terms for ADU construction. We can recommend lenders experienced with ADU projects who understand construction draws and permit timelines.

Ready to Start Your ADU Project?

Get a free site assessment and learn what you can build on your property. We'll provide preliminary pricing and answer all your questions. No obligation.

Calculate ADU Cost Call (858) 434-7166

Ready to Start Your Project?

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