Examples of different ADU types

ADU vs JADU vs SB-9: What's the Difference?

ADUs (Accessory Dwelling Units), JADUs (Junior Accessory Dwelling Units), and SB-9 (Senate Bill 9) offer distinct ways for owners to expand their property's capacity and value.

ADUs are independent buildings equipped with their own kitchen, bathroom, and entrance, constructed on the same lot as a primary residence. JADUs are smaller units created within the existing footprint of a single-family home, often by converting a bedroom or garage. SB-9 allows the construction of up to 2 units on a single-family lot or the subdivision of a single-family lot into separate lots, with each lot permitted to have two ADUs.

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ADU

Accessory Dwelling Units, or ADUs, are small, independent living spaces with their own kitchen, bathroom, and entrance, all located on the same property as a larger home. These units can either be attached to the main house or stand-alone, making them a flexible option for those looking to earn rental income or provide housing for family members. Thanks to recent changes in California laws, it's now much easier for homeowners to build these units, opening up new possibilities for housing solutions and community living.

California's ADU laws streamline the permitting process, limit local agency discretion, and establish statewide standards. Key provisions include:

  • Size & Setbacks
    State law sets maximum size limits (typically 850 sq. ft. for a one-bedroom or smaller unit and 1,000 sq. ft. for units with two or more bedrooms) and mandates minimal setbacks (normally 4 feet from side and rear property lines). However, local jurisdictions can have stricter regulations.
  • Parking
    State law generally prohibits local agencies from requiring replacement parking when an existing garage or carport is converted to an ADU or when the ADU is located within 1/2 mile of public transit.
  • Owner Occupancy
    State law generally prohibits local agencies from requiring owner occupancy of either the primary dwelling or the ADU until January 1, 2025. Local jurisdictions may impose owner occupancy requirements after that date.
  • Permitting
    Local agencies must approve or deny ADU applications within 60 days of a completed application.
  • Utility Connections
    Local agencies cannot require a new or separate utility connection fee or capacity charge that is disproportionate to the burden of the proposed ADU based on its size or impact.
  • Limitations
    Fire sprinklers may be required in some situations. HOA rules may complicate ADU construction.

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Related Articles

Traditional California house with an ADU in the back of the property lot

What is an ADU?

An Accessory Dwelling Unit (ADU) is a small living space on the same property as a main house. While the concept seems simple, there's a lot more to consider. ADUs can come in various shapes and sizes and provide a range of benefits. They can provide additional living space, offer supplemental income from rent, and help tackle housing shortages.

ADU construction in California with architect and contractor reviewing building plans

What are the different types of ADUs?

The specific type of ADU that can be built depends heavily on local regulations, lot size, and homeowner preferences. Some common types of ADUs include attached or detached structures, basement, attic, or garage conversions, junior ADUs, and SB-9 property lot splits.

California ADU entrance with homeowner's key

What are the benefits of building an ADU?

Some benefits of building an ADU include providing additional living space for family members or guests, generating rental income, increasing the value of the home, and offering flexibility in how to use the property.

ADU vs JADU, side by side

What's the difference between an ADU and a JADU?

ADUs and JADUs offer distinct advantages and disadvantages. ADUs provide greater space, independence, and rental income potential, while JADUs offer a more affordable and compact living solution within the primary residence. The optimal choice depends on the homeowner's needs, financial considerations, and local regulatory environment.

ADU vs SB-9, side by side

What's the difference between an ADU and an SB-9 project?

While both ADUs and SB-9 projects contribute to increasing housing density in California, they differ in scope, regulatory framework, and impact on neighborhood character. ADUs offer a more incremental approach to adding housing to existing properties, while SB-9 projects involve a more transformative approach through lot splitting and creating multiple new dwelling units.

SB-9 vs JADU, side by side

What's the difference between an SB-9 project and a JADU?

JADUs and SB-9 projects represent distinct approaches to increasing housing density. JADUs offer a more incremental and affordable way to add living space within existing homes, while SB-9 projects involve a more transformative approach through lot splitting and the creation of multiple new dwelling units.