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What is an ADU: Accessory Dwelling Units

What Is an ADU: Types, Laws, and How to Start Building in 2024

With California’s 2024 laws, building an Accessory Dwelling Unit has become easier and more flexible for homeowners. In this guide, we’ll cover what ADU stands for, the benefits, new regulations, and tips for finding reliable ADU builders in Sacramento.

What is an ADU In Real Estate

If you’re wondering, what is an ADU home in real estate terms, it’s a small, independent living space on the same property as a main home, offering its own kitchen, bathroom, and bedroom. By the ADU definition, it can be a detached building, an addition to your house, or even a converted garage or basement.

ADUs are popular in California because they add affordable housing options without requiring new land. They’re often used as rental units, guest houses, or spaces for family members. ADUs are also more flexible than traditional home additions, as they can be sold or rented separately in many areas.

The Difference Between an ADU, JADU, and a Home Addition

ADU (Accessory Dwelling Unit)

JADU (Junior Accessory Dwelling Unit)

Home Addition

Size

Up to 1,200 square feet, detached or attached

Up to 500 square feet, within existing main house walls

Can be any size depending on property and zoning limits

Independence

Fully independent unit with own kitchen, bathroom, and entrance

Limited independence, often shares kitchen or bathroom with main house

Fully integrated with main house, no separate entrance

Permitting and Costs

Requires a full building permit, often more costly due to separate utilities

Easier and typically less costly to permit, streamlined regulations

Requires standard building permits, may have more restrictions

Uses

Rental, long-term guest suite, or separate family living

Guest room, office, or limited family living space

Added family space or extra rooms

Rental Potential

High rental potential, can be rented independently

Limited rental potential, typically not rented separately

Cannot be rented out independently

Property Value Impact

Significantly increases property value due to rental income potential

Adds moderate value but less than a full ADU

Adds value, especially when adding bedrooms or bathrooms

Privacy

High privacy with separate entrance and living space

Some privacy, shares amenities with the main house

No additional privacy

Types of ADUs in California

The ADU meaning covers a variety of unit types, including detached buildings, garage conversions, and basement units, each with unique benefits for homeowners:

  • Detached ADU: A separate structure from the main house, like a backyard cottage. It provides complete independence and privacy.
  • Attached ADU: An addition connected to the main house, sharing a wall but having a separate entrance. This option maintains proximity while offering distinct living spaces.
  • Garage Conversion ADU: Transforms an existing garage into a livable unit. This is one of the most cost-effective ways to utilize existing space.
  • Basement Conversion ADU: Converts a basement into a separate living area. This option is ideal for homes with unused basement space.
  • Junior ADU a.k.a. JADU: A smaller unit, up to 500 square feet, within the main house. It often shares some facilities, like a bathroom, with the primary residence.

If you’re unsure, which ADU type will be the best fit for your property type and needs, contact a local general contractor with relevant experience, proper licensing, and solid reviews and ask for a free quote with clear cost breakdowns.

Benefits of an Accessory Dwelling Unit

  • Extra Income: Renting out an ADU can provide a steady income stream, helping you offset mortgage costs or save for future expenses.
  • Increased Property Value: An ADU adds living space, which typically increases the value of your property. Buyers often see ADUs as valuable features, making your home more attractive if you choose to sell.
  • Flexible Living Options: ADUs are perfect for multigenerational families. They offer a private space for elderly parents, adult children, or visiting family, all while staying close to home.
  • Affordable Housing: In California, ADUs help address the housing shortage by adding affordable, small-scale housing options. This contributes to the community by creating more rental options in high-demand areas.
  • Sustainable Growth: ADUs promote sustainable, in-fill development. Instead of expanding into new land, you’re building on existing property, which is better for the environment.

New ADU Laws in California

  • Simplified Permits: Many applications are approved within 60 days, which reduces wait times and hassle.
  • Less Restrictive Rules: You can now build an ADU that better fits your property and personal needs.
  • Reduced Fees: Some fees for building ADUs have been lowered or removed, making it more affordable.
  • Fewer Parking Requirements: ADUs no longer need separate parking spaces if they’re near public transit.
  • Support for Sustainable Building: The laws encourage eco-friendly materials and energy-efficient designs.

How To Build an ADU

  1. Understand Local Regulations
    Start by checking your city’s ADU rules on size limits, setbacks, and permits. Visit your local planning department to ensure compliance with all requirements.

  2. Set Your Budget
    Outline a clear budget, including costs for permits, construction, and utility connections. Having a realistic budget helps avoid surprises during the project.

  3. Choose the Best Location
    Decide where the ADU will go on your property. Consider privacy, accessibility, and any landscaping or site adjustments you may need to make.

  4. Hire an Experienced Contractor
    Look for contractors with specific ADU experience in California. They’ll understand the regulations and help streamline the permit and building process.

  5. Plan for Utility Connections
    Ensure the ADU will have separate water, electricity, and possibly gas connections. Check if separate meters are required and factor these costs into your budget.

  6. Define Long-Term Plans
    Decide on the ADU’s primary purpose—whether it’s for family, rental income, or future resale. This will guide the design, layout, and finishes you choose.

FAQ

Can I build an ADU on my property?

In Sacramento, homeowners can build up to two ADUs on a single lot, as long as there is an existing or planned main residence. ADUs can be either attached or separate structures and must meet all local zoning and building regulations.

What are the size limits for ADUs in Sacramento?

A detached ADU in Sacramento can be up to 1,200 square feet. For attached ADUs, the size limit is either up to 50% of the main home’s size or 850 square feet for a studio or one-bedroom and 1,000 square feet for a two-bedroom—whichever gives you the most space.

Can I rent out my ADU?

California's Assembly Bill 1033 allows rending out, selling, and transferring ADUs in Sacramento separately from your main property.