An Accessory Dwelling Unit (ADU) is a secondary, self-contained residence located on the same property as a primary home. As housing needs evolve, many homeowners are turning to ADUs as a flexible way to expand how their property is used.

Beyond adding livable space, an ADU can increase property value and create new opportunities – whether for extended family, visiting guests, rental income, or a private workspace.

Los Angeles allows three distinct types of Accessory Dwelling Units (ADUs) and one type of SB9 Unit on residential parcels. Use this guide to understand the development standards, required permits, and applicable regulations for each type.

ADU Types at a Glance

General Permit Process

In Los Angeles, detached Accessory Dwelling Units (ADUs) can typically be permitted under two different regulatory pathways:

• Local Ordinance ADU (LAMC)
• State ADU (California Government Code)

Both allow ADUs on a residential property, but they operate under different rules and development standards. They have different restrictions for height, setbacks, and other zoning factors. Understanding the distinction can significantly impact what is possible on your site.

Most new ADUs in Los Angeles today are permitted under State ADU regulations, because they often allow greater flexibility and fewer zoning restrictions.

Key Regulatory Frameworks

Regulation	Applies To	Key Provision
LAMC § 12.22 A.33	Attached & Detached ADUs	Los Angeles City standards for height, setbacks, lot coverage, and design
Gov. Code § 65852.2	All ADUs statewide	State ADU law — sets minimum rights and limits local restrictions
Gov. Code § 65852.22	JADUs only	Junior ADU standards — conversion of existing space, owner-occupancy
SB 9 (Gov. Code § 66411.7)	Single-family zones	Allows lot splits and two primary units on SFR lots
AB 2221 / SB 897	All ADUs	2023 amendments — reduced setbacks, increased height allowances

General Permit Process

Step	Action	Est. Timeline
1	Pre-Application Research — zoning, easements, utilities	1–2 weeks
2	Design & Construction Documents	per client
3	LADBS Plan Check Submittal (electronic or over-counter)	Varies
4	Plan Check Review & Corrections	8–12 weeks
5	Permit Issuance — pay fees, pull permit	1–2 weeks
6	Construction & Inspections	6–9 months
7	Certificate of Occupancy / Final Inspection	2–4 weeks

Regulatory Considerations for ADUs

Before building an Accessory Dwelling Unit on your property, it is important to understand several legal and regulatory factors that may affect what can be built and how the space can be used.

• Zoning and Building Codes
  Local zoning regulations determine where ADUs are allowed, as well as requirements such as maximum size, height limits, and setbacks from property lines. In addition, all ADUs must comply with building codes that govern structural safety, fire protection, and habitability.
• Rental and Landlord-Tenant Regulations
  If you plan to rent your ADU, it is important to understand the applicable landlord-tenant laws in your jurisdiction. These regulations define the rights and responsibilities of both landlords and tenants and may affect lease agreements, rental terms, and occupancy requirements.
• Owner-Occupancy Rules
  Some jurisdictions require the property owner to live on-site if an ADU is present. This can affect whether both the primary residence and the ADU can be rented at the same time. Local regulations should be reviewed carefully before planning a rental strategy.
• Subdivision and Condo Conversions
  In certain situations, it may be possible to subdivide a property or convert units into condominiums so that they can be sold separately. However, these processes involve complex zoning and real estate regulations and typically require professional guidance.

Because ADU regulations can vary significantly between jurisdictions, understanding these legal considerations early in the process can help ensure that a project moves forward smoothly.

Resources

Resource	Description
LADBS ADU Portal	Los Angeles Department of Building & Safety — permits, plan check, fee calculator
HCIDLA Rent Registry	Register rental ADUs and access tenant protection information
HCD ADU Handbook	California Dept. of Housing — statewide ADU guidance and model ordinance
Michael Matthews Studio	Leader in the design of custom ADUs in Los Angeles

Our Role

Designing and building an ADU involves navigating zoning regulations, building codes, and permitting requirements while also creating a space that feels comfortable, functional, and thoughtfully integrated with the existing property. The right design approach can make the difference between simply adding square footage and creating a valuable, well-designed living environment.

At Michael Matthews Studio, we work closely with homeowners to evaluate the potential of their property and develop ADU designs that balance regulatory requirements, construction feasibility, and architectural quality. Our experience with Los Angeles zoning and permitting processes allows us to guide projects efficiently from early feasibility through design and approval.

Whether you are considering a detached ADU, converting an existing structure, or exploring ways to maximize the potential of your property, we can help you understand what is possible and develop a clear path forward.

If you are thinking about building an ADU in Los Angeles, we would be happy to discuss your property and help you determine the best strategy for moving your project forward.

Contact Michael Matthews Studio to begin exploring the possibilities for your ADU project. You may reach us at info@michaelmatthewsstudio.com

Disclaimer: This guide is provided for informational purposes only and reflects regulations as of 2026. Development standards, fees, and procedures are subject to change. Always verify current requirements with LADBS and consult a licensed architect or attorney before proceeding.