How big can an ADU be in San Bernardino?

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

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

Build costs typically range $100,000 – $220,000, or $155 – $220 per square foot.

Verified March 14, 2026

ADU Regulations in San Bernardino, California

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

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

San Bernardino County · CA · Pop. 225,000

Max ADU Size

1,200

sq ft detached

Rear Setback

4 ft

Permit Timeline

60 days

Build Cost

$100,000 – $220,000

Zoning

Allowed ADU Types

✓Detached ADU

✓Attached ADU

✓JADU (Junior ADU)

✓Garage Conversion

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

ADUs allowed by-right per California state law

Source: City of San Bernardino — Accessory Dwelling Units · San Bernardino Development Code Section 19.02

Dimensions

Size & Setback Requirements

Detached

1,200

sq ft max

JADU

500

sq ft max

Attached

50% of primary home, max 1,200 sq ft

Setbacks

front

Same as primary dwelling

side

4 ft

rear

4 ft

Max height: 16 ft

Lot coverage: Per underlying zone

Many San Bernardino lots are spacious and suitable for detached ADUs

Permitting

Permit Process

Department

San Bernardino Community & Economic Development

Review Timeline

60 days

Permit Fees

$4,000 – $10,000

Impact Fees

Impact fees waived under 750 sq ft

Required Documents

›Site plan
›Floor plans
›Elevations
›Title 24 energy compliance
›Structural drawings (new construction)

San Bernardino's lower fee structure makes it easier to pencil out ADU projects

Visit San Bernardino Community & Economic Development →

Infrastructure

Utilities & Requirements

Solar

Required

Parking

Not required

Separate Meter

Optional

Fire Sprinklers

See note

Sewer: Connect to existing sewer; East Valley Water District or City Water Department

Fire Sprinklers: Not required unless primary structure requires them

Parking: No additional parking required

Financials

ADU Costs in San Bernardino

Typical Build Cost

$100,000 – $220,000

Cost per Sq Ft

$155 – $220

Monthly Rental

$1,100 – $1,900/mo

Property Value Added

Adds $90,000 – $180,000 to property value

Available Grants & Programs

★CalHFA ADU Grant Program available

Inland Empire market offers affordable ADU construction costs

Use the free ADU Cost Calculator →

Free Service

Get Contractor Quotes in San Bernardino

Connect with licensed local ADU contractors. Takes 2 minutes, no obligation.

Get Free Quotes

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 San Bernardino Community & Economic Development

Explore More

Nearby Cities in San Bernardino County

Fontana

Max 1,200 sq ft · $110,000 – $230,000

Ontario

Max 1,200 sq ft · $115,000 – $240,000

Rancho Cucamonga

Max 1,200 sq ft · $150,000 – $310,000

Victorville

Max 1,200 sq ft · $115,000 – $240,000

Rialto

Max 1,200 sq ft · $130,000 – $265,000

Hesperia

Max 1,200 sq ft · $115,000 – $235,000

San Bernardino Quick Facts

Max size1,200 sq ft
Rear setback4 ft
Permit timeline60 days
Build cost$100,000 – $220,000
Rental income$1,100 – $1,900/mo
Owner occupancyNot required

Get Free Quotes

Licensed San Bernardino ADU contractors, no obligation.

Get My Free Quotes

Official Source

City of San Bernardino — Accessory Dwelling Units

San Bernardino Development Code Section 19.02

Last verified: March 14, 2026

Free Tools

→ ADU Cost Calculator → ROI Calculator

Stay Updated

ADU rules change often.

Get notified when San Bernardino's regulations update, plus guides on permitting and financing.