How to Design, Permit, and Build an ADU in California: A Step-by-Step Guide

As a trusted, licensed, & professional construction company specializing in ADU development, we understand will help you build your ADU in every step of the process. Here’s a detailed breakdown of what it takes to successfully design, permit, and build an Accessory Dwelling Unit (ADU) in California.

1. Planning & Analysis: Setting the Foundation

Before starting your ADU project, it’s crucial to evaluate the feasibility of not only building on your property but the financial analysis to go along with it.

• Analyze the numbers – Your first step should always be to run the numbers so you understand the full scope of the costs involved in building your ADU. This is not only important for rental feasibility but even if you are planning to occupy the ADU yourself it is still important to have a complete financial picture.
• Check local zoning & lot eligibility – California law allows ADUs statewide, but cities may have specific restrictions on lot size, placement, and number of ADUs per property.
• Understand size, height & setback requirements – Most jurisdictions allow ADUs up to 1,200 sq. ft., with varying height limits and required setbacks from property lines.
• Choose your ADU type – Decide between a detached unit, an attached ADU, a garage conversion, “carve out”, or a junior ADU (JADU) within your main home.

2. Design & Finishes: Bringing Your Vision to Life

Once Step one is done, it’s time to design your ADU for optimal functionality for your planned use.

• Work with our ADU designer – A well-planned ADU maximizes space, meets local codes, and enhances property value.
• Interior design – We help you take into account, budget, intended use, and personal style to select the right finishes for your ADU in our exclusive design center here in Campbell CA.
• Ensure compliance with state & local building codes – California’s ADU regulations are streamlined, but city-specific requirements can still apply.
• Plan for livability – If renting, consider features like private entrances, reduced consumables, & simplicity. If occupying yourself, consider your wants, needs, & personal preferences.

3. Permitting & Financing: Handling The Paperwork

Permitting & Financing  are key steps that requires proper documentation and consideration prior to building.

• We submit site plans, construction drawings, and engineering on your behalf – These documents ensure your ADU meets structural and safety requirements.
• Acquire your financial backing (if needed) – There are a variety of ways to finance your ADU project, we will help you explore your options so you can select the right one for you.
• Obtain building permits before construction – Construction cannot begin until permits are officially issued.

4. Construction & Inspections: Bringing Your ADU to Reality

Once permits are in place, construction can officially begin.

• Site preparation & foundation work – If building from scratch proper grading and foundation reinforcement are essential.
• Framing, roofing & structural work – This stage shapes the ADU, including walls, roof installation, and door/window placement.
• Plumbing & electrical – Installation of plumbing & electrical per the plans.
• Interior & exterior finishes – Flooring, cabinets, lighting, and landscaping complete the ADU and make it move-in ready.
• Schedule inspections at key stages – We will schedule with the city electrical, plumbing, structural, and final inspections.
• Obtain a Certificate of Occupancy – This official document confirms the ADU is safe and legal to inhabit.

5. Renting or Occupying Your ADU: Maximizing Your Investment

With construction complete, it’s time to put your ADU to use.

• If renting – Understand lease agreements, find the right high quality renters, & Start Collecting Your Monthly Cash-Flow!
• If occupying yourself – Move in and start enjoying your new space!

Why Choose Bayfront ADU for Your Accessory Dwelling Unit Build?

At Bayfront ADU, we specialize in design, permitting, and construction, ensuring a smooth and stress-free process. Our team handles everything from planning to final inspections, giving you a truly turn-key solution to your build.

Thinking about building an ADU on your property? Contact us today for a free consultation!