How big can an ADU be in San Diego?

Detached ADUs in San Diego can be up to 1,200 sq ft. Attached ADUs: 50% of primary, max 1,200 sq ft. JADUs up to 500 sq ft.

How much does it cost to build an ADU in San Diego?

Build costs typically range $160,000 – $480,000, or $275 – $425 per square foot.

Verified March 14, 2026

ADU Regulations in San Diego, California

Q: What are the setback requirements for ADUs in San Diego?

Front: Same as primary. Side: 4 ft. Rear: 4 ft.

San Diego County · CA · Pop. 1,400,000

Max ADU Size

1,200

sq ft detached

Rear Setback

4 ft

Permit Timeline

30–60 days for standard review

Build Cost

$160,000 – $480,000

Zoning

Allowed ADU Types

✓Detached ADU

✓Attached ADU

✓JADU (Junior ADU)

✓Garage Conversion

Max per lot: 2 ADUs✓ No owner-occupancy required

Single-family lots may have 1 ADU + 1 JADU

Source: City of San Diego — ADU Information · SDMC Section 141.0302

Dimensions

Size & Setback Requirements

Detached

1,200

sq ft max

JADU

500

sq ft max

Attached

50% of primary, max 1,200 sq ft

Setbacks

front

Same as primary

side

4 ft

rear

4 ft

Max height: 16 ft detached; match primary for attached

Conversions of existing structures may have zero setbacks

Permitting

Permit Process

Department

City of San Diego Development Services Department

Review Timeline

30–60 days for standard review; Express Review available

Permit Fees

$4,000 – $18,000

Impact Fees

Waived for ADUs 750 sq ft and under

Required Documents

›Site plan
›Architectural floor plans
›Elevation drawings
›Title 24 energy compliance
›Structural calculations (new construction)

Visit City of San Diego Development Services Department →

Infrastructure

Utilities & Requirements

Solar

Required

Parking

Not required

Separate Meter

Optional

Fire Sprinklers

See note

Sewer: Connect to city sewer; capacity fee may apply

Fire Sprinklers: Required if primary home has them; otherwise not required

Parking: No additional parking required

Financials

ADU Costs in San Diego

Typical Build Cost

$160,000 – $480,000

Cost per Sq Ft

$275 – $425

Monthly Rental

$1,600 – $4,000/mo

Property Value Added

Typically adds $180,000 – $350,000 to property value

Available Grants & Programs

★CalHFA ADU Grant (up to $40,000)
★San Diego Housing Commission programs available

Coastal areas may have additional design review requirements

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Disclaimer: Information is compiled from publicly available municipal codes for general informational purposes only. It does not constitute legal, zoning, or construction advice. Regulations change frequently. Always verify with your local planning department. Last verified: March 14, 2026. Verify with City of San Diego Development Services Department

Explore More

Nearby Cities in San Diego County

Chula Vista

Max 1,200 sq ft · $140,000 – $300,000

Oceanside

Max 1,200 sq ft · $160,000 – $330,000

Escondido

Max 1,200 sq ft · $155,000 – $320,000

Carlsbad

Max 1,200 sq ft · $175,000 – $360,000

El Cajon

Max 1,200 sq ft · $150,000 – $305,000

Vista

Max 1,200 sq ft · $150,000 – $305,000

San Diego Quick Facts

Max size1,200 sq ft
Rear setback4 ft
Permit timeline30–60 days for standard review
Build cost$160,000 – $480,000
Rental income$1,600 – $4,000/mo
Owner occupancyNot required

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Official Source

City of San Diego — ADU Information

SDMC Section 141.0302

Last verified: March 14, 2026

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