What is the maximum ADU size allowed in Diamond Bar?

Detached ADUs in Diamond Bar can be up to 1200 square feet.

ADU Builders & Contractors in Diamond Bar, CA

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

The average cost ranges from $148,000 to $323,000, or $198-373 per square foot.

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

The permit process typically takes 60 to 120 weeks in Diamond Bar.

With 159 verified ADU contractors serving Diamond Bar, CA, homeowners have plenty of options for their accessory dwelling unit project. Local contractors ready to help specialize in everything from design-build to permit navigation.

📊 ADU Quick Facts for Diamond Bar

Avg. Cost/sqft

$198-$373

Permit Timeline

60-120 weeks

Max Size

1200 sqft

Setbacks

4ft sides

Top 159 ADU Contractors in Diamond Bar

🏗️

#1YELLOWSTONE WORKX INC

Diamond Bar, CA

Yellowstone Workx Inc — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction.

View Profile 📞 (626) 888 0714

🏗️

#2ALLIANT CONSTRUCTION SERVICES INC

Diamond Bar, CA

Alliant Construction Services Inc — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 6+ years experience.

View Profile 📞 (818) 612 8200

🏗️

#3V C CONSTRUCTION & DEVELOPMENT

Diamond Bar, CA

V C Construction & Development — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 14+ years experience.

View Profile 📞 (909) 236 1745

🏗️

#4QUIJANO L

Diamond Bar, CA

Quijano L — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction.

View Profile 📞 (909) 914 8561

🏗️

#5ARORA JAY

Diamond Bar, CA

Arora Jay — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 38+ years experience.

View Profile 📞 (909) 576 9814

🏗️

#6KITCHEN AND FLOORING CENTER INC

Diamond Bar, CA

Kitchen And Flooring Center Inc — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 14+ years experience.

View Profile 📞 (909) 594 5020

🏗️

#7JUNG YOUNG CHAI

Diamond Bar, CA

Jung Young Chai — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 6+ years experience.

View Profile 📞 (310) 990 7565

🏗️

#8DATANG BUILDING SERVICE INC

Diamond Bar, CA

Datang Building Service Inc — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction.

View Profile 📞 (626) 271 5797

🏗️

#9STEWART CONSTRUCTION COMPANY CORP

Diamond Bar, CA

Stewart Construction Company Corp — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction.

View Profile 📞 (909) 301 1017

🏗️

#10RIVA PROPERTY MANAGEMENT

Diamond Bar, CA

Riva Property Management — licensed ADU contractor in Diamond Bar, CA. Detached ADU construction. 6+ years experience.

View Profile 📞 (909) 708 6699

View All 159 Contractors →

💰 How Much Does an ADU Cost in Diamond Bar?

Garage Conversion

$69,000 - $129,000

Converting existing garage to living space

Detached ADU

$148,000 - $323,000

New standalone unit (600-1,200 sqft)

Permit & Fees

$1,105 - $5,105

Plan check, permits, utility connections

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

❓ Frequently Asked Questions About ADUs in Diamond Bar

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

The average cost to build an ADU in Diamond Bar ranges from $148,000 to $323,000, or approximately $198 to $373 per square foot. Garage conversions typically cost $69,000 to $129,000.

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

The ADU permit process in Diamond Bar 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 Diamond Bar?▼

In Diamond Bar, 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 Diamond Bar?▼

Diamond Bar 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 Diamond Bar?▼

No parking is required for ADUs in Diamond Bar 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)

Ready to Build Your ADU in Diamond Bar?

Get free quotes from top-rated local contractors

Find Contractors Now

← View all contractors in California