Perched in the scenic hills east of San Jose, Mount Hamilton offers expansive landscapes, privacy, and some of the most breathtaking views in the Bay Area. For homeowners in this beautiful region, an Accessory Dwelling Unit (ADU) is the perfect way to make the most of your land—whether you’re planning to house family, host guests, or generate income.

At Royalty Builders, we specialize in custom ADU design and construction in Mount Hamilton, offering end-to-end services that include feasibility studies, architectural planning, permitting, construction, and finishing. Whether you’re converting a garage, building a detached guesthouse, or creating a private office space, we deliver ADUs that are as functional as they are beautiful.

🛠️ Full-Service ADU Design + Build in Mount Hamilton

We believe building an ADU should feel exciting—not stressful. That’s why our team handles every step of the project in-house, from the first consultation to final inspection.

✅ Feasibility & Site Evaluation – We analyze slope, access, utility connections, and zoning
✅ Custom Design Solutions – We tailor the ADU layout to match your needs and landscape
✅ Permit Coordination – We work with Santa Clara County to secure all necessary permits
✅ High-Quality Construction – Built to last, even in rural or elevated terrain
✅ Final Approvals & Move-In Ready Finish – Fully inspected, finished, and code-compliant

Our experience with hillside construction and remote locations gives us an edge when working in areas like Mount Hamilton where terrain and access can add complexity.

🧱 Types of ADUs We Build in Mount Hamilton

We design and build a wide range of ADU types based on your property’s layout, topography, and intended use:

• Detached ADUs – Private, freestanding units ideal for guests, tenants, or aging relatives

• Garage Conversions – Efficiently convert existing structures into cozy living spaces

• Attached ADUs – Build a separate unit connected to your main home with its own entrance

• Above-Garage ADUs – Perfect for maximizing vertical space and views

• Junior ADUs (JADUs) – Compact units under 500 sq. ft. with a kitchenette and shared bath access

Each unit is carefully planned to integrate with your home and environment, while offering flexibility, privacy, and value.

📍 Why Build an ADU in Mount Hamilton?

Mount Hamilton’s large lots and private settings make it an ideal location for building a secondary dwelling. Whether you’re seeking income, flexibility, or family convenience, an ADU is a smart addition.

✔️ Earn Passive Rental Income – Offer long- or short-term stays with beautiful views and quiet surroundings
✔️ Support Multi-Generational Living – House family members while maintaining independence
✔️ Create Private Work or Hobby Space – Escape the distractions of the main home
✔️ Increase Long-Term Property Value – ADUs are highly desirable to future buyers
✔️ Take Advantage of California ADU Incentives – Streamlined approvals and reduced development fees

💲 ADU Construction Costs in Mount Hamilton

Because Mount Hamilton features unique terrain and rural conditions, ADU costs may vary more than in urban or suburban areas. Here’s what to expect:

• Garage Conversions: starting at $100,000–$160,000

• Detached ADUs: range from $200,000–$425,000+, depending on grading and access

• Attached ADUs: typically $175,000–$325,000

• Above-Garage Units: start around $250,000+, with added structural requirements

📌 We offer detailed, transparent estimates based on your land, existing infrastructure, and desired design. We also help you explore financing or staged construction options if needed.

📝 Permits for ADU Construction in Mount Hamilton – What You Need to Know

Unlike most cities, Mount Hamilton falls under unincorporated Santa Clara County, which means your ADU must meet county-level building, zoning, and environmental regulations. Fortunately, Royalty Builders has experience working with rural and hillside permitting processes.

The permitting process includes:

🔹 Zoning Verification & Site Review
We confirm your lot is zoned for ADU use under Santa Clara County guidelines and assess slope stability, septic systems (if applicable), access roads, and fire requirements.

🔹 Design Approval
We prepare site plans, architectural drawings, and Title 24 energy compliance reports. For rural or hillside properties, this may include erosion control, grading plans, and environmental reviews.

🔹 Permit Application Submission
Our team submits all documents to the County Planning and Development Department, monitors review status, and coordinates any necessary revisions.

🔹 Inspections & Final Approval
We manage all construction inspections—from foundation to framing to final—ensuring your ADU meets code and receives a Certificate of Occupancy upon completion.

✅ Santa Clara County follows state ADU laws, including:

• No minimum lot size

• Up to 1,200 sq. ft. for detached ADUs

• Reduced parking requirements in many cases

• Streamlined 60-day approval timeline

Our expertise with county-level permitting, rural grading ordinances, and hillside development makes us the ideal partner for ADU projects in Mount Hamilton.

👷 Why Choose Royalty Builders as Your Mount Hamilton ADU Contractor?

Building in a remote or elevated location requires more than just standard construction knowledge. You need a team that understands topography, access, code compliance, and construction logistics—and that’s where Royalty Builders excels.

Here’s what you can count on:

• 🧱 Full-Service Design + Build Team

• 🌄 Hillside & Rural Construction Experience

• 🏗️ County Permit Expertise

• 📋 Clear Proposals and Realistic Timelines

• 🧑‍💼 Dedicated Project Manager from Start to Finish

Whether you’re dreaming of a cozy cottage for guests or a stunning second home with panoramic views, we’ll help you build it—beautifully and correctly.

❓ FAQ – ADUs in Mount Hamilton

Q: Do I need to level my lot before building an ADU?
A: Not always. We’ll evaluate the slope and recommend solutions like grading, retaining walls, or stilts where appropriate.

Q: Can I build an ADU off-grid in Mount Hamilton?
A: Yes, but you’ll need proper systems for water, power, and waste. We can coordinate off-grid design or utility hookups based on your location.

Q: What if my property uses a septic system?
A: We coordinate with the County and local environmental agencies to determine capacity and upgrade options if needed.

Q: Can I build more than one unit?
A: Many properties allow both an ADU and a Junior ADU (JADU). We’ll help you maximize your property legally.

📞 Contact Us – Start Your Mount Hamilton ADU Today

Whether you’re building for your family, income, or peace of mind, Royalty Builders is your trusted partner for ADU construction in Mount Hamilton. We know the land. We know the rules. And we know how to build it right.

📞 Call us today and schedule your free consultation.

Let’s turn your hillside property into a flexible, functional, and future-ready home.