ADUs on San Francisco’s West Side: Basics and Benefits

What if your garage or backyard could help pay your mortgage? Many Los Angeles–area homeowners are turning underused space into accessory dwelling units that create flexibility and long-term value. If you are in Carson, Los Angeles, Long Beach, or Glendale, you have options thanks to California’s ADU-friendly laws. In this guide, you will learn the basics, local checkpoints, costs, timelines, and first steps so you can plan with confidence. Let’s dive in.

ADU and JADU basics

An accessory dwelling unit is a secondary home on the same lot as your main residence. You can build it as a detached cottage, attach it to the home, or convert existing space. A junior ADU is a smaller unit created within the primary home that typically shares utilities and may have a separate entrance.

On typical Los Angeles–area lots, you will most often see:

• Garage conversions that become a studio or one-bedroom with a compact kitchen and bath.
• Detached backyard cottages that provide more privacy and yard separation.
• Attached additions that carve out an independent suite from the main house.
• JADUs formed from a bedroom or accessory space inside the house.

Most local ADUs are studios or one-bedrooms between about 350 and 800 square feet. Homeowners use them for long-term rental income, space for adult children or parents, or a flexible office or studio.

Eligibility: state rules and local checks

California law opened the door for more ADUs and limits many local barriers. Statewide guidance from the California Department of Housing and Community Development explains that qualifying ADUs receive ministerial approval when they meet objective standards. Cities can set their own size, height, and design rules, but they cannot block compliant ADUs.

You still need to confirm what applies on your parcel. Before you design anything, check:

• Zoning and whether ADUs are allowed for your lot type.
• Maximum sizes, height limits, and setbacks for your city.
• How many ADUs are allowed on your parcel type.
• Parking rules and available exemptions, such as for conversions or proximity to transit.
• Sewer, water, and electrical capacity, and whether separate meters are required or optional.
• Any homeowners association covenants or historic-preservation rules that affect exterior design or placement.

For city-specific rules and permits, start with your local authority:

• City of Los Angeles: Los Angeles Department of Building and Safety
• City of Long Beach: Long Beach Development Services
• City of Carson: Carson Community Development
• City of Glendale: Glendale Planning Division

Popular ADU options in Los Angeles

Garage conversion

A garage conversion is often the fastest route. You keep the existing footprint and convert the space into a habitable unit. You may need new plumbing lines, insulation, heating and cooling, and an upgraded electrical panel. The main tradeoff is the loss of covered parking and storage. Some owners add a new driveway space or build an ADU above a new garage to regain parking.

Detached backyard cottage

If you have yard space, a detached ADU offers privacy and light for both homes. Plan for foundations, drainage, and access for construction. Pay attention to separation from the main house, landscaping for privacy, and how the new path to the unit will work day to day.

ADU over a garage

Building above a garage saves yard area and can create a comfortable one-bedroom layout. Expect structural reinforcement, a stair design that meets code, and careful attention to height limits and neighbor privacy.

Attached addition or JADU

An attached unit or junior ADU is a good fit for multigenerational living. Shared systems can reduce cost. Plan for sound separation, clear private entries, and simple interior circulation.

Parking, size, and utilities

Parking requirements for ADUs are lighter than they used to be. Under state rules, many conversions do not require new parking, and proximity to transit can trigger waivers as well. The eligibility and documentation for these exemptions differ by city. Confirm the process with your planning department and document your conditions early.

Size limits vary by city. State law sets minimum allowances, and many cities allow a detached ADU in the several-hundred-to-900-square-foot range, with larger sizes possible depending on zoning and lot size. Height limits and setbacks also vary, especially for two-story or over-garage designs.

Utilities can be a significant line item. Conversions may tie into existing systems. Detached units often require new trenching for sewer and water, panel upgrades, and sometimes separate meters. Your city and utility providers will guide what is required and what is optional.

Permitting steps and realistic timelines

A smooth ADU project follows a clear path. While each city’s process is slightly different, the most common steps look like this:

1. Preliminary zoning check and a quick conversation with your city’s planning or building department.
2. Site survey and schematic design with a designer or architect familiar with ADUs.
3. Construction drawings and engineering for structure, grading if needed, and utilities.
4. Permit application and fee payment at your city’s building department.
5. Plan review cycles with corrections and resubmittals as needed.
6. Permit issuance, contractor mobilization, city inspections, and a final occupancy sign-off.

Timelines vary with project scope and city staffing. A simple garage conversion that meets objective standards can move faster than new construction. Typical expectations in the Los Angeles area:

• Feasibility and design: 2 to 8 weeks.
• Plan check: 4 to 12 weeks for simple cases, 2 to 6 months for typical projects, and 6 to 12 months or more for complex sites.
• Construction: 1 to 3 months for small conversions, 4 to 9 months for detached ADUs.

From first decision to move-in, a 6 to 18 month total timeline is common. The best way to protect your schedule is to submit a complete, well-documented plan set and respond quickly to any plan check comments.

What it costs in the LA area

Costs depend on scope, finishes, and site conditions. Broad regional ranges are:

• Garage conversion: about $40,000 to $120,000 depending on utilities and structural work.
• Detached ADU, roughly 400 to 900 square feet: about $150,000 to $400,000. Site work and utilities are major drivers.
• Two-story or high-end builds: $300,000 or more.
• JADU inside the main home: often under $50,000 if changes are mostly interior.

Cities charge plan check and building permit fees. Some jurisdictions reduce or waive certain impact fees for smaller ADUs. Confirm specifics with your city permit counter.

A best practice is to add a 10 to 30 percent contingency to your budget. Factors like sewer lateral replacement, soil conditions, or panel upgrades can appear once you open up walls or dig trenches.

Livability and long-term value

A well-executed ADU can improve how you live today and what your home is worth in the future.

Benefits you will notice:

• Rental income that helps offset mortgage and ownership costs.
• Multigenerational living with privacy and flexibility for changing needs.
• Marketability to future buyers who value flexible space or income potential.
• Long-term asset value from a quality, code-compliant improvement.

Tradeoffs to plan for:

• Parking and storage. Converting a garage removes covered parking. Explore driveway options or an over-garage design.
• Privacy and design. Good entries, sightlines, and landscaping go a long way toward comfort for both homes.
• Property management. If you plan to rent, decide on tenant screening, lease terms, and day-to-day management.
• Taxes and insurance. New construction usually increases assessed value to some degree and may change coverage needs. Consult your tax advisor and insurer.

First steps checklist

Use this quick plan to move from idea to action:

• Verify your zoning and ADU allowance with your city’s planning or building department.
• Measure lot dimensions and note setbacks, easements, and any unusual site conditions.
• Check HOA rules or historic-district requirements, if applicable.
• Evaluate sewer, water, and electrical capacity. Ask about potential upgrades or separate meters.
• Map out parking. Identify whether you qualify for a parking exemption.
• Choose an ADU type that fits your lot and goals: garage conversion, detached, attached, or JADU.
• Hire a designer or ADU-experienced contractor and get a preliminary site plan and budget.
• Build in a contingency. Plan for 10 to 30 percent beyond base estimates.

Trusted resources to start your research

• Review statewide guidance from the California Department of Housing and Community Development.
• For permits and plan check in Los Angeles, go to the Los Angeles Department of Building and Safety.
• Check local rules in Long Beach, Carson, and Glendale.
• For research and policy analysis on ADUs in California, explore the Terner Center for Housing Innovation.

Ready to plan your next step?

Whether you want rental income, space for family, or a future-ready home, an ADU can be a smart move when you plan the details right. If you are buying, selling, or preparing a property strategy that includes an ADU or tenant placement, connect for experienced guidance and a practical game plan. Schedule a free neighborhood consultation with Michael Soon.

FAQs

What is the difference between an ADU and a JADU in Los Angeles?

• An ADU is a stand-alone or attached secondary home with its own kitchen and bath, while a JADU is a smaller unit within the main house that typically shares utilities and has a separate entrance.

How long does it take to permit an ADU in the City of Los Angeles?

• Plan check for simple ADUs can take 4 to 12 weeks, typical projects often take 2 to 6 months, and complex cases can take 6 to 12 months or more before permit issuance.

How much does a garage conversion cost around Los Angeles County?

• A basic conversion commonly ranges from about $40,000 to $120,000, depending on utilities, structural upgrades, and finish level.

Do I need to provide parking for my ADU near transit in Los Angeles?

• Many ADUs qualify for reduced or waived parking, especially conversions and those near transit, but you must confirm eligibility and documentation with your city’s planning or building department.

Can I rent an ADU short-term in Long Beach or Glendale?

• Many cities allow long-term rentals but place restrictions on short-term rentals; review the current local ordinances and any HOA rules before listing.

Will building an ADU increase my property taxes in the Los Angeles area?

• New construction typically increases assessed value to some degree; consult your tax professional and insurer to understand how an ADU would affect your taxes and coverage.