From Permit to Completion: The Complete Guide to Building an ADU in LA

Thinking about adding extra space to your home? Building an ADU in Los Angeles might be just what you need. It’s great for family, renting out, or creating a home office. Plus, it adds value and makes your property more flexible. The process can seem tricky, but don’t worry. This guide will walk you through every step – from getting permits to moving in – so you know exactly what to expect.

Step 1. Understand What Type of ADU You Can Build

Before you begin, decide what kind of unit fits your property and budget. You can choose from:

• Detached ADUs. A small, separate home in your backyard (typically 400-1,200 sq. ft.).
• Attached ADUs. Connected to your existing home, sharing one wall.
• Garage conversions or JADUs. Transforming existing space into a livable unit.

Each type has size and zoning rules. In Los Angeles, detached ADUs can be up to 1,200 sq. ft. Junior ADUs (JADUs) are usually limited to 500 sq. ft. The first step is to know your lot size and local rules.

Step 2. Permits and Planning

It used to take months to get a permit. Now the process is faster. New state laws, like AB 1332, made it easier. Many cities offer pre-approved plans and online applications. Homeowners can save money on design and time by doing this.

You’ll usually need these:

1. Site plan showing your existing home, yard, and proposed ADU.
2. Floor plans and elevations with plumbing and electrical layouts.
3. Energy and structural calculations that meet California’s Title 24 standards.
4. Utility connections (gas, water, sewer) and possible upgrades.

If you work with a specialized contractor likeADUScale, most of these steps are handled for you. They handle city requirements and submit your plans. They also make sure everything meets code. This saves you the stress of dealing with different departments.

Step 3. ADU Construction – From Foundation to Finish

Once your permit is approved, it’s time to build. The ADU Construction phase typically takes 4-6 months, depending on size, materials, and site conditions. Prefabricated ones can be faster – sometimes ready in as little as 10 weeks.

Construction usually includes:

• Site preparation. Grading, utility trenching, and foundation work.
• Framing and roofing. Creating the main structure.
• Interior finishes. Drywall, flooring, cabinetry, and paint.
• Final inspections. Ensuring plumbing, electrical, and safety codes are met.

A real-life example: one Los Angeles homeowner added a 600 sq. ft. detached ADU in their backyard for $185,000. It took five months from permit to completion. Now, the unit rents for $2,300 per month – enough to cover most of their mortgage.

Step 4. Inspections and Move-In

The city will conduct a number of inspections before you are allowed to rent or occupy your ADU. These examine the stability of your foundation, water pressure, smoke detectors, and electrical system. A Certificate of Occupancy, which is your official permission to use the space, will be given to you after you are accepted.

Tip: Keep all permits, inspection reports, and utility records in one folder. This will be handy if you’re refinancing or selling your home.

Common Mistakes to Avoid

Even with simplified laws, homeowners still make a few common mistakes:

• Skipping feasibility checks. Always verify setback rules and utility access before starting.
• Underestimating costs. Add 10-15% for unexpected expenses like soil testing or drainage fixes.
• DIY plans. Professional drawings may seem expensive upfront, but they prevent delays and rejections.

Partnering with a licensed builder ensures smoother project flow and fewer surprises. Companies like ADUScale handle everything – from design to final inspection – so you don’t have to coordinate multiple contractors.

Step 5. Enjoy the Benefits

Once complete, your ADU opens a world of possibilities. You can rent it out for passive income, create a private home office, or welcome aging parents close to home. Many California homeowners earn $2,000-$3,500 per month from ADU rentals – while increasing property value by 25-35%.

ADUs encourage more sustainable living in addition to financial gain. They shorten commutes, improve community cohesion, and make better use of the land that already exists.

FAQ

1. How long does it take to build an ADU in LA?
Most projects take 4-8 months, depending on design complexity and city approvals. Prefab units are usually faster.

2. Do I need parking for my ADU?
In most LA neighborhoods, parking is not required if your property is within half a mile of public transit.

3. What’s the average cost to build an ADU in California?
Costs range from $150,000-$350,000, depending on size, finishes, and site conditions.

4. Can I rent out my ADU immediately?
Yes, once you have a Certificate of Occupancy, you can rent it out long-term.

5. Where can I find pre-approved ADU plans?
Cities like Los Angeles and San Diego offer pre-approved designs. You can download them directly from their official planning websites.

Final Remarks

In Los Angeles, constructing an ADU is more than just remodeling. It is an investment in the future of your property. It’s an investment in your property’s future. If you have the right team, the right permits, and a solid plan, you can turn an empty yard into a finished home. In less than a year.