Across Los Angeles County, ADUs have become one of the most effective ways to create additional housing on an existing property. Whether you already have an older ADU that needs updating or you’re converting a garage into a new living space, remodeling an ADU can increase comfort, improve property value, and open the door to long-term rental income.
But because Los Angeles County includes many different cities — each with its own planning departments and building requirements — ADU remodeling can quickly become overwhelming without a clear roadmap.
Here’s what you need to know before starting an ADU remodel in Los Angeles County.
An ADU (Accessory Dwelling Unit) is a smaller secondary home located on the same lot as a primary residence. ADUs can be built as:
Detached backyard units
Attached additions
Garage conversions
Interior conversions within an existing home
They’re often called granny flats or guest houses, but legally they’re full residential units.
In Los Angeles County, ADU remodeling is often driven by the need for more usable space and better functionality — especially in dense neighborhoods where expanding a primary home isn’t always possible.
Common reasons homeowners remodel ADUs include:
Increasing rental income potential
Creating housing for extended family
Updating older units to meet current code
Improving layout and space efficiency
Modernizing finishes for better resale value
Permits are a major part of ADU remodeling in LA County. Even if you’re not changing the footprint, you may still need approvals depending on the work involved.
Permits commonly required include:
Building permits
Electrical permits
Plumbing permits
Mechanical/HVAC permits
Planning approvals (depending on your city and property)
The exact requirements depend on whether your property falls under the City of Los Angeles or another local jurisdiction.
Garage conversions and detached structure conversions are some of the most popular ADU projects in Los Angeles County. They’re often faster than building from scratch — but still require compliance with current building codes.
Conversions typically require updates to:
Insulation and drywall
Electrical systems and subpanels
Plumbing and sewer tie-ins
Fire separation and rated construction
Windows and egress requirements
ADU remodeling projects must meet life safety and livability standards, including:
Smoke and CO detectors
Proper emergency exits
Heating and ventilation
Plumbing and electrical compliance
Minimum ceiling heights and room standards
Even if your ADU “already exists,” it may not meet modern requirements — especially if it was built decades ago.
Los Angeles County is made up of many cities (and unincorporated areas), and ADU requirements can differ depending on where your property sits.
Your remodel may be affected by:
Height limits
Setback rules
Parking requirements
Utility upgrades
Design review (especially in certain neighborhoods)
To avoid delays and budget surprises:
Start with feasibility and code review
Prioritize layout efficiency in smaller spaces
Plan upgrades around inspections
Work with an ADU builder who understands LA County processes
ADU remodeling in Los Angeles County can be a major advantage for homeowners — especially when done legally, efficiently, and with a plan that meets current code. Whether your goal is rental income, family housing, or simply better use of your property, a well-executed remodel can add serious value.