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What Is an ADU?

An accessory dwelling unit (ADU) is a self-contained living space on your property — separate from your main house — with its own kitchen, bathroom, and entrance. Homeowners build them for aging parents, adult kids, a rental unit, or simply more usable space than the main house provides.

Orange County has seen a sharp rise in ADU projects over the past few years, driven by state laws that made them easier to permit and build. Progressive Builders handles the design, permitting, and construction as one accountable team, so you’re not coordinating between separate contractors.

Detached ADU

A standalone structure elsewhere on your lot.

Attached ADU

Built onto your existing home, sharing a wall.

Garage Conversion ADU

Your existing garage, converted into a full living space.

Junior ADU (JADU)

A smaller unit built within your home’s existing footprint, up to 500 sq ft.

Where We Build

Progressive Builders installs ADUs across Orange County and Select Neighboring LA County Areas.

California ADU Regulations

California has made ADUs significantly easier to build in recent years. Some state-level basics as of 2026: detached ADUs can generally be built up to 1,200 sq ft on most residential lots, with minimum 4-foot side and rear setbacks. ADUs built within an existing structure like a garage can keep existing setbacks even under 4 feet. Cities must review complete ADU applications on a “ministerial” basis — staff-level approval without a discretionary hearing — generally within 60 days. JADUs are capped at 500 sq ft, must be within your home’s existing footprint or an attached structure, and can share a bathroom with the main house.

State law sets the floor, but individual OC cities can layer on their own requirements around design review, parking, or lot coverage.

This is general information, not legal advice — every project should be confirmed against your specific city’s current requirements.

ADU FAQ

How much does an ADU cost in Orange County?

Every ADU is different — cost depends on the type, size, site conditions, and finishes you choose. We’ll give you a clear estimate after reviewing your property.

How long does it take to build an ADU?

Depends on type and city permitting speed — a garage conversion typically moves faster than a new detached structure.

Do I need a permit?

Yes — though state law requires cities to process complete applications quickly and without a discretionary hearing.

Can Progressive Builders handle the permitting process?

Yes — design, permitting, and construction are handled by one team.

What is an ADU, and is it right for me?

A Junior ADU is a smaller unit — up to 500 sq ft — built within your existing home or garage. A lower-cost option if you don’t need a fully separate structure and don’t mind sharing a bathroom.