ADU Builder in Los Angeles County

Los Angeles County is one of the strongest ADU markets in California — high rents, flexible zoning, and county-level permitting that moves faster than most incorporated cities. Apex Homes specializes in building ADUs here, managing everything from design and permits to construction so you’re not coordinating it yourself. If you’re ready to build, we’ll tell you exactly what’s possible on your lot for free. 

ADU Regulations in Los Angeles County

Los Angeles County follows California state ADU law while applying its own local standards for both single-family and multi-family properties.

Single-family lots (R-1)

• One detached or attached ADU + one Junior ADU (JADU) permitted
  • Detached ADUs: up to 1,200 sq ft; attached 
  • ADUs: up to 50% of the primary dwelling’s size
  • JADUs capped at 500 sq ft, located within the primary dwelling
• Side and rear setbacks: 4 ft minimum
• Unit separation: 6 ft for ADUs ≤800 sq ft; 10 ft (or attachment required) for ADUs >800 sq ft
• Height: up to 16 ft; up to 18 ft if within ½ mile of public transit

Multi-family lots (R-2+)

• Up to 8 detached ADUs permitted, or attached ADUs equal to 25% of existing units — whichever is greater
• Conversions of existing non-livable space (garages, storage) also permitted
• Same setback and height requirements apply

Two-story ADUs are permitted up to the applicable zoning height limit, excluding basements. Front-yard placement is not permitted for detached ADUs.

Apex Homes handles zoning verification, setback calculations, and code compliance — included in your free feasibility study.

The Los Angeles County ADU Permitting Process

To obtain an ADU permit in Los Angeles County, homeowners should first confirm their property’s zoning and review the County’s ADU standards.

Free Feasibility Study

Apex checks your zoning, lot size, setbacks, and utility connections at no cost, before you commit to anything.

Select a Pre-Approved Plan

Choose from LA County-compatible ADU layouts. No custom design review required. Permits move faster and cost less.

Apex Submits Your Permit Package

We prepare and submit all site-specific documents (site plan, floor plans, elevations, structural details, Title 24) to the Los Angeles County Department of Public Works Building and Safety Division.

Permit Issued

Typically 2–4 months. LA County issues permits digitally, allowing construction to begin promptly. Apex manages all county follow-up and responds to plan-check comments.

Construction & Inspections

Apex builds your ADU and manages all county inspections. We deliver a finished, move-in ready unit, typically within 5 months of your feasibility study.

Check my Property Eligibility

---

 

Browse ADU Floor Plans

Apex offers a range of 1, 2, and 3-bedroom ADU floor plans designed to meet California’s building standards and fit a variety of lot sizes. Each plan includes all required documentation for permitting — site plan, elevations, structural details, and Title 24 energy compliance — so your project moves faster from approval to build.

Why Build an ADU in Los Angeles County?

Los Angeles County’s high housing demand and diverse neighborhoods make it an excellent place to invest in an ADU. Homeowners can generate steady rental income while adding long-term value to their property, creating a smart financial investment.

ADUs also provide flexible living options for families, allowing space for aging parents, adult children, or guests while maintaining privacy and independence. With careful planning, these units can enhance your property’s functionality without sacrificing style or comfort.

The county supports ADU development through clear regulations, flexible zoning, and streamlined permitting processes. Apex Homes guides homeowners through the entire process, from design to construction, making it simple to bring your ADU vision to life.

Book a free one-on-one consultation with our team to explore how an ADU can maximize your property’s potential in Los Angeles County.