Adu Cost San Diego Complete Guide

By Cali Dream Construction | San Diego, CA | License #1054602

A Complete Guide to ADU Costs in San Diego (2026)

Building an Accessory Dwelling Unit (ADU) in San Diego is one of the smartest investments you can make as a homeowner. Whether you want rental income, multigenerational living space, or increased property value, understanding ADU costs upfront is essential for planning your project.

In San Diego County, a complete ADU typically costs between $150,000 and $400,000, with most projects ranging from $200,000 to $300,000 for a 600-800 square foot unit. Here's everything you need to know about ADU costs in San Diego.

ADU Cost Breakdown by Type

Detached ADU (New Construction)

Garage Conversion ADU

Converting an existing garage is the most cost-effective option, typically costing $80,000 to $150,000. You save on foundation and framing costs, but still need electrical, plumbing, insulation, and finishes.

Junior ADU (JADU)

A JADU is created within your existing home (500 sq ft max) and costs $50,000 to $100,000. JADUs require less permitting and can share bathrooms with the main house.

What's Included in ADU Construction Costs

Hard Costs (70-75% of Budget)

• Foundation: $15,000 - $35,000
• Framing: $20,000 - $40,000
• Roofing: $8,000 - $20,000
• Electrical: $10,000 - $25,000
• Plumbing: $15,000 - $35,000
• HVAC: $8,000 - $15,000
• Kitchen: $15,000 - $40,000
• Bathroom: $10,000 - $25,000
• Flooring: $5,000 - $15,000
• Windows/Doors: $5,000 - $15,000

Soft Costs (25-30% of Budget)

• Permits: $5,000 - $15,000 (varies by city)
• Architectural Plans: $5,000 - $15,000
• Engineering: $3,000 - $8,000
• Utility Connections: $5,000 - $20,000
• Impact Fees: Waived in most San Diego jurisdictions through 2026

San Diego ADU Regulations (2026)

California's ADU laws make San Diego one of the best places to build. Key rules include:

• Size limits: Up to 1,200 sq ft for detached ADUs, 800 sq ft for attached
• Setbacks: 4-foot rear and side setbacks
• Height: Up to 16 feet (detached), 25 feet if near transit
• Parking: Not required if within 1/2 mile of public transit
• Owner occupancy: Not required for new ADUs (through 2025)
• Impact fees: Waived for ADUs under 750 sq ft

ADU Rental Income Potential in San Diego

San Diego ADUs command strong rental rates due to our housing shortage:

• Studio (400 sq ft): $1,500 - $2,000/month
• 1-Bedroom (600 sq ft): $2,000 - $2,800/month
• 2-Bedroom (800 sq ft): $2,500 - $3,500/month

With rental income of $2,000-$3,000/month, most San Diego ADUs pay for themselves in 7-12 years.

How to Finance Your San Diego ADU

• Home Equity Loan/HELOC: Use existing home equity at competitive rates
• Cash-Out Refinance: Refinance your primary mortgage for ADU funds
• Construction Loan: Short-term financing that converts to permanent loan
• CalHFA ADU Grant: Up to $40,000 for pre-development costs

Why Choose Cali Dream Construction for Your ADU

Cali Dream Construction has built over 100 ADUs throughout San Diego County. We handle everything from design to permits to construction, making your ADU project simple and stress-free.

Our ADU services include:

• Free site evaluation and feasibility assessment
• In-house architectural design
• Complete permit processing
• Full construction management
• Transparent fixed-price contracts

Ready to explore ADU options for your property? Call us at (858) 434-7166 for a free consultation, or try our ADU Cost Calculator for an instant estimate.