What is the maximum ADU size allowed in Fullerton?

Detached ADUs in Fullerton can be up to 1200 square feet.

ADU Builders & Contractors in Fullerton, CA

Q: How much does it cost to build an ADU in Fullerton?

The average cost ranges from $150,000 to $325,000, or $200-375 per square foot.

Q: How long does it take to get an ADU permit in Fullerton?

The permit process typically takes 60 to 120 weeks in Fullerton.

Fullerton, CA is home to 368 ADU contractors ready to help. From initial permits to final inspection, these local professionals know Fullerton's building codes and can guide your project from concept to completion.

📊 ADU Quick Facts for Fullerton

Avg. Cost/sqft

$200-$375

Permit Timeline

60-120 weeks

Max Size

1200 sqft

Setbacks

4ft sides

Top 368 ADU Contractors in Fullerton

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#1TERRA UNIVERSAL INC

Fullerton, CA

Terra Universal Inc — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (714) 578 6118

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#2HIT DESIGN BUILD INC

Fullerton, CA

Hit Design Build Inc — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (213) 776 1801

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#3ABEL CONSTRUCTION & ROOFING INC

Fullerton, CA

Abel Construction & Roofing Inc — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (213) 500 7362

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#4EPIC BUILD & REMODEL INC

Fullerton, CA

Epic Build & Remodel Inc — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (213) 696 2531

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#5MORNING TOWN CONSTRUCTION

Fullerton, CA

Morning Town Construction — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (714) 743 6560

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#6S E M CONSTRUCTION GROUP

Fullerton, CA

S E M Construction Group — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (714) 688 6702

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#7NEXUS DEVELOPMENT

Fullerton, CA

Nexus Development — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (562) 314 1198

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#8WON GUN CHO

Fullerton, CA

Won Gun Cho — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (213) 414 8966

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#9JUAN CARLOS SUAREZ

Fullerton, CA

Juan Carlos Suarez — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (714) 749 3728

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#10ERIGONIK INC

Fullerton, CA

Erigonik Inc — licensed ADU contractor in Fullerton, CA. Detached ADU construction.

View Profile 📞 (806) 401 2979

View All 368 Contractors →

💰 How Much Does an ADU Cost in Fullerton?

Garage Conversion

$70,000 - $130,000

Converting existing garage to living space

Detached ADU

$150,000 - $325,000

New standalone unit (600-1,200 sqft)

Permit & Fees

$1,117 - $5,117

Plan check, permits, utility connections

* Costs vary based on size, finishes, site conditions, and contractor. Get quotes from multiple Fullerton contractors to compare pricing.

❓ Frequently Asked Questions About ADUs in Fullerton

How much does it cost to build an ADU in Fullerton?▼

The average cost to build an ADU in Fullerton ranges from $150,000 to $325,000, or approximately $200 to $375 per square foot. Garage conversions typically cost $70,000 to $130,000.

How long does it take to get an ADU permit in Fullerton?▼

The ADU permit process in Fullerton typically takes 60 to 120 weeks. California law requires cities to approve or deny ADU permits within 60 days of receiving a complete application.

What are the ADU size limits in Fullerton?▼

In Fullerton, detached ADUs can be up to 1200 square feet. Attached ADUs are limited to 50% of the primary dwelling or 1,200 sqft, whichever is less. Junior ADUs (JADUs) are limited to 500 sqft and must be within the existing home.

What is the setback requirement for ADUs in Fullerton?▼

Fullerton requires 4-foot setbacks from side property lines and 4-foot setbacks from rear property lines for new ADU construction. Converted structures (like existing garages) may maintain their current setbacks.

Do I need to provide parking for my ADU in Fullerton?▼

No parking is required for ADUs in Fullerton if your property is within half a mile of public transit, in a historic district, part of an existing multi-family building, or if the ADU is a garage conversion. Otherwise, one space may be required.

Also See ADU Contractors In

Los Angeles (3215)San Diego (2582)San Francisco (2170)Sacramento (1551)Riverside (925)Fresno (904)Anaheim (784)Irvine (760)

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