Antioch is one of the fastest-growing communities in Contra Costa County, offering homeowners a rare combination of space, affordability, and long-term investment potential. Building an Accessory Dwelling Unit (ADU) is a strategic way to expand your living space, create rental income, or prepare for multigenerational living—all without the cost of moving.

At Royalty Builders, we offer turnkey ADU design and construction services tailored to your goals and your property. Whether you’re planning a detached guest suite, converting a garage, or designing a backyard rental unit, we handle everything—from permitting to move-in ready completion.

Types of ADUs We Build in Antioch

Antioch’s diverse lot sizes and home styles make it ideal for a variety of ADU configurations. At Royalty Builders, we tailor every ADU to match your property, lifestyle, and goals.

We specialize in:

• Detached ADUs – Private, freestanding units perfect for guests, tenants, or family

• Attached ADUs – Seamlessly connected additions that expand your home’s layout

• Garage Conversions – Affordable way to transform unused garage space into livable square footage

• Above-Garage ADUs – Smart, vertical expansion for maximum use of lot space

• Basement Conversions – Ideal for unlocking lower-level square footage in split-level homes

Every unit is thoughtfully designed to meet Antioch’s building codes and your aesthetic preferences.

Full-Service ADU Design + Build in Antioch

We make it simple with our design-build process. With Royalty Builders, you won’t have to manage architects, engineers, contractors, and city officials—we handle everything in-house with one experienced team.

Our comprehensive service includes:

• Site assessment and zoning review

• Architectural design and 3D renderings

• Structural engineering and Title 24 energy compliance

• Full permitting with the City of Antioch and Contra Costa County (if applicable)

• Construction with high-quality materials and finishes

• Final walkthrough, inspections, and utility connections

We take care of the details, so you can focus on the big picture.

How Much Does It Cost to Build an ADU in Antioch?

Building an ADU in Antioch is more cost-effective than in many other Bay Area cities, making it a smart investment for homeowners looking to increase livable space and future value. We provide detailed, transparent pricing with no surprises.

Typical ADU pricing in Antioch:

• Garage Conversion: $110,000 – $160,000

• Attached ADU: $170,000 – $270,000

• Detached ADU: $190,000 – $330,000+

• Above-Garage ADU: $210,000 – $360,000

Need financing? We can help you explore loan options, equity strategies, and payment plans to make your ADU project accessible and stress-free.

Permits for ADU Construction in Antioch – What You Need to Know

Antioch follows California’s ADU-friendly housing laws, but the city still has its own zoning and building requirements that must be addressed. Our experienced team works closely with local planning departments to get your permits approved quickly and correctly.

We handle:

• Property research and lot eligibility

• Permit documentation and architectural plan submittal

• Responses to plan corrections and building department feedback

• Scheduling inspections and securing final approvals

• Ensuring your ADU meets all code and occupancy standards

We know the system—so your project stays on track from day one.

Why Build an ADU in Antioch?

With strong housing demand, larger lots, and increasing rental interest, Antioch is the perfect place to invest in an ADU. Whether you’re thinking short-term or long-term, adding an ADU here is a smart way to create opportunity.

Here’s why more homeowners are building ADUs in Antioch:

• 🏡 Extra space for extended family or aging parents

• 💼 A quiet home office, studio, or remote workspace

• 💰 Generate passive rental income in a high-demand market

• 📈 Increase home value and appeal to future buyers

• 🔁 Adapt your property to meet changing family needs

ADUs in Antioch offer both lifestyle improvement and financial return.

Frequently Asked Questions – ADUs in Antioch

Q: Can I build an ADU on my property in Antioch?
A: In most residential zones, yes. We’ll evaluate your property to confirm eligibility and layout options.

Q: What’s the maximum ADU size allowed in Antioch?
A: You may be able to build up to 1,200 sq. ft. for a detached ADU, depending on your lot. We’ll help you determine the maximum based on your zoning.

Q: Is parking required for an ADU in Antioch?
A: Often no—especially if the unit is near transit or converted from an existing structure. We’ll verify requirements for your address.

Q: How long does the ADU process take?
A: Most projects take 6–10 months from design through final construction. We’ll give you a personalized project timeline after your consultation.

Contact Royalty Builders – Antioch’s Local ADU Experts

Ready to unlock your property’s potential with a beautiful, fully permitted ADU in Antioch? Royalty Builders is here to guide you through every step—from planning to permits to building. Let’s bring your vision to life.

📞 Contact us today and schedule your free ADU consultation in Antioch.

Efficient space. Smart design. Built with Royalty.