Adu Blog

Accessory Dwelling Unit Types

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Exterior Attached Additions can be more feasible when it comes to Cape style homes. The homeowner has a lot more freedom when it comes to parameters to build within. As long as the addition is within the zoning laws, the ADU isn’t limited by existing space. This allows for more flexibility to create a space that is ADA accessible while also allowing the ADU to be accessed from within the existing home.

Pros and Cons


  • Space is less limited
  • Don’t need to worry about fitting within a existing parameter
  • Won't be losing existing space within the existing house
  • Availability to extend and connect into existing plumbing, electrical, and HVAC
  • Family member will be under the same roof


  • Space to build is limited by local zoning
  • Need to extend existing plumbing, electrical, and HVAC
  • New construction, from foundation to facade
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A separate, exterior, stand-alone structure on the main home's property, like a cottage or detached garage. Attached ADU—These are built as an addition to the primary home structure.

A Detached Accessory Dwelling Unit (ADU) is a dwelling unit that meets the following criteria:

  • It is located on the same lot, under the same ownership as, and subordinate to a single-family dwelling unit.
  • It is physically separated from and located in a different structure than the primarydwelling unit.
  • It is intended for use as a complete, independent living facility.
  • It includes facilities for living, sleeping, eating, cooking, and sanitation for not more than one family.
  • Detached Accessory Dwelling Units are also called Detached Accessory Apartments.
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Any existing permitted space located within an existing single-family home or within a permitted accessory structure in the R-1 (Single-Family Residential) zone can be converted into an accessory dwelling unit (ADU) with approval of building permits. Existing second-story additions to detached accessory structures cannot be converted to an ADU, such as a storage room. Any proposed ADU conversion must comply with the development standards of Title 9 of the Garden Grove Municipal Code and the California Building Code, including:

  • Proof of Permits: The property owner must provide copies of building permits for the space that will be converted.
  • Parking: No additional parking is required for the ADU; however, if a garage conversion is proposed, the required parking spaces for the primary unit must be replaced on-site. The replacement parking can be designed as open parking spaces. The total number of required parking spaces for the primary unit is based on the number of bedrooms :
        1-4 bedrooms: 4 parking spaces
        5-7 bedrooms: 6 parking spaces
        8 or more bedrooms: 8 parking spaces
  • Minimum Unit Size: The minimum unit size must comply with the requirements of the California Residential Code
  • Building Code Requirements: All proposed ADU conversions must comply with the requirements of the California Residential Code (CRC) and all model codes, including the Plumbing Code, Mechanical Code, Energy Code, and the California Green Building Code Standards
  • Approval of an ADU requires that the property owner reside on the property and occupy one of the units.
  • The ADU must be served by the same utility connections as the primary unit, and no separate utility meters will be permitted.
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Junior Accessory Dwelling Units (JADUS

A Junior ADU (or JADU) is a new category of dwelling units created by the State of California. There are several distinctions between a standard ADU and a JADU detailed in the table below. The main difference is that a JADU is not required to have a dedicated bathroom.

Junior Accessory Dwelling Unit (JADU) General Provisions

  • There is a limit of one JADU per lot zoned for single-family residences. The JADU shall be constructed within walls of a proposed or existing single-family residence.
  • Maximum size is 500 square feet, however, an additional 150 square foot expansion beyond the physical dimensions of the existing structure is permitted strictly to accommodate ingress and egress to JADU.
  • The JADU shall include a separate entrance from the main entrance to the proposed or existing single-family residence.
  • The JADU shall include an efficiency kitchen, which includes:
    • Cooking facility with appliances (240-volt service outlets now permitted)
    • Food preparation counter and storage cabinets that are of reasonable size in relation to the size of the JADU
    • No restriction on maximum waste line diameter
  • A deed restriction is required and must include the following stipulations:
    • Prohibition on the sale of the JADU separate from the sale of the single-family residence.
    • Restriction on the size and attributes of the JADU.
    • If a JADU is rented, the unit shall not be rented for a period of less than 30 consecutive calendar days
    • Owner occupancy of one of the units on-site is required* *Owner-occupancy is not required if the owner is another governmental agency, land trust, or housing organization.
  • The JADU may share sanitation facilities (i.e. bathroom/shower) with a primary residence.