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Accessory Dwelling Units (ADUs)

Learn about the benefits of Accessory Dwelling Units (ADUs) and the design, building and planning process.

Accessory dwelling units (ADUs) go by many different names, including in-law units, granny flats, or backyard cottages. An ADU is an additional, small home that you can build on your property. They have a kitchen, a bathroom, and a separate entrance. 

  • New detached prefabricated ADU in San Anselmo with outdoor deck and seating.
    New detached prefabricated ADU in San Anselmo.
  • Converted garage to ADU in Corte Madera with lush greenery surrounding entrance.
    Interior conversion in Mill Valley.
  • Interior view of living room, part of bedroom and part of kitchen of an ADU that was created through the conversion of an existing structure in San Anselmo.
    Converted existing structure in San Anselmo.
  • Converted garage to ADU in Corte Madera.
    Converted garage in Corte Madera.

Different Types of ADUs

There are different types of ADUs, including: 

  • Attached ADUs: Attached ADUs are attached directly to the main house, located in the back, side, or front. 
  • Detached ADUs: Detached ADUs are a separate buildings located on the same property as the main house.
  • Junior Accessory Dwelling Units (JADUs): JADUs are smaller versions of ADUs. They are often created by converting an existing bedroom. They do not need to have a full kitchen, but they must have a wet bar.

Benefits for the Owner and Community

Like other parts of the Bay Area, Marin County is experiencing a severe housing shortage. The creation of ADUs is one solution we can use to help address our affordable housing challenges. Benefits of building an ADU include: 

  • Rental Income: You can rent an ADU to a tenant. This will provide both much-needed housing and generate a steady source of income. 
  • Housing for Caregivers/Loved Ones:  ADUs are often used to house caregivers for people who need support or medical care.
  • Increase in Property Value: ADUs can increase the value of your property by providing more living space. 

How to Create an ADU

If you're interested in building an ADU in unincorporated Marin, we encourage you to get in touch with our Planning team. You can also find helpful resources on ADUMarin.


Page updated June 27, 2024