New ADU Plans & Permit Coordination in California
Haven't built yet? We help California homeowners understand the process, coordinate plans and permit documentation, and start their ADU project the right way.
Planning an ADU and Not Sure Where to Start?
This page is for homeowners who haven't built yet — if you're asking questions like these, you're in the right place:
- "I want to build an ADU in my backyard."
- "Can I add an ADU to my property?"
- "I need plans for an ADU."
- "I want to convert my garage into an ADU legally, before doing the work."
- "I don't know where to start with permits."
- "Can someone help coordinate the plans and permit process?"
If you already have an ADU, garage conversion, or other structure that was built without permits, this isn't the right starting point — see Legalizing Existing Work instead.
What Type of ADU Are You Planning?
Every project is different — here's a general starting point based on what you're considering.
Planning to convert your garage into an ADU, with permits from the start.
Learn more →Need help with plans, documentation, or permit coordination generally.
Learn more →Planning a Detached ADU
A detached ADU is a standalone unit, separate from the main house — often placed in a backyard or side yard. Because it's a separate structure, planning one generally involves site placement, utility connections, and setback considerations in addition to the usual design and permitting steps.
Start Planning Your Detached ADU
Legal ADU Pro can help you understand what a detached ADU project on your property typically involves.
Request a Property Review →Planning an Attached ADU
An attached ADU is a unit connected to the existing house — for example, built onto the side or rear of the home, or created within an addition. Because it shares a wall or structure with the main house, it generally involves different structural and design considerations than a fully detached unit.
Start Planning Your Attached ADU
Legal ADU Pro can help you understand what an attached ADU project on your property typically involves.
Request a Property Review →Converting Your Garage Into an ADU — the Right Way
If you're planning to convert your garage into an ADU and haven't started the work yet, you have the opportunity to do it as a new, permitted project — rather than building first and legalizing it afterward. The planning and permit sequence is different from legalizing a garage that's already been converted without permits.
See our full guide to planning a permitted garage conversion ADU →
Already converted your garage without permits? See Garage Conversion Legalization instead.
ADU Plans & Drafting
Most new ADU projects need some combination of a site plan, floor plan, and elevations before they can be submitted for permits. What's required depends on the project and the reviewing jurisdiction.
What Legal ADU Pro Helps Coordinate
- Understanding what type of plans your project is likely to need
- Coordinating with licensed architects, engineers, or drafters for stamped plans when required
See our full guide to ADU plans, drafting & design coordination →
Understanding the Permit Process for a New ADU
While every project and jurisdiction is different, planning and permitting a new ADU generally involves a different starting point than legalization — there's no existing structure or permit history to research. In brief, it typically moves from an initial project review, through plans and permit submittal, to inspections and final sign-off.
Discuss Your New ADU Project
Legal ADU Pro can help you understand what this process typically looks like for your property.
Request a Property Review →Coordination With Other Professionals
Depending on your project, a new ADU can involve several parties working together — you, the reviewing building department, and often a licensed architect, engineer, surveyor, or contractor. Legal ADU Pro helps identify who is likely needed for your specific project and helps coordinate that process, rather than acting as any of those licensed roles ourselves.
Property & Project Review
Most homeowners start with an initial review of their property and project goals. This helps identify what type of ADU may fit, what the general process is likely to involve, and what information you'll want to gather before moving forward.
What Homeowners Should Prepare
- Property address and general lot information
- A general idea of what you're hoping to build (detached, attached, or garage conversion)
- Any existing site plans, surveys, or property documentation you already have
- Your general timeline and goals for the project
Start with an initial conversation about your property and project.
Get Started →California ADU Considerations
California has statewide laws that generally affect how local cities and counties review and approve ADU projects, alongside each jurisdiction's own zoning and building requirements. These rules affect things like allowable size, placement, and approval timelines, and they can change over time and vary by city or county.
Questions About Planning a New ADU
Legal ADU Pro helps coordinate the plans and documentation your project needs and helps connect you with licensed architects, engineers, or drafters when stamped plans or specialized drawings are required. We are not a licensed architect or engineer ourselves.
It depends on your lot, your goals, and local zoning. Detached and attached ADUs generally involve different design and permitting considerations. An individual property review helps identify which direction makes sense before you invest in plans.
Many homeowners choose to convert a garage into an ADU as a new, permitted project. This is a different process than legalizing a garage that was already converted without permits. See our dedicated guide on planning a permitted garage conversion ADU.
Timelines vary significantly based on the project, the reviewing jurisdiction's current workload, and how complete the plans and documentation are at submittal. An individual review helps set realistic expectations for your specific project.
Often, yes, depending on the scope of the project and the requirements of the reviewing jurisdiction. Legal ADU Pro helps identify when licensed professionals are likely needed and can help coordinate with them.
This page is for homeowners who have not yet built their ADU and want to plan and permit it correctly from the start. Our legalization services are for homeowners who already have an unpermitted ADU or structure and need to bring it into compliance.
Feasibility depends on lot size, setbacks, existing structures, utility access, and local zoning requirements. See our New ADU Feasibility Review for a general overview of what's typically involved.
Ready to Start Planning Your ADU?
Request an initial property review and understand what the process typically involves for your project.
Request a Property Review → Call 310-570-2885