Apply for an ADU or JADU in Fairfax

Fairfax residents looking to add an Accessory Dwelling Unit (ADU) or Junior Accessory Dwelling Unit (JADU) to their property can find a supportive and streamlined process. These units are excellent for providing additional housing options or income, aligning with community values of diversity and affordability.

According to State law, the Town must provide an expedited approval process for ADUs that includes only ministerial review and shall not include any discretionary processes. This means that if you design your ADU to comply with all the zoning standards and architectural review criteria listed in the Zoning Ordinance, your project may be approved by the Town without going through the discretionary design review process or other public hearings.

Need to know

  • Fees: ADU application fee is $250. Building permit fees range from $997 for minor additions to $1,511 for major additions. JADU fees mirror those of ADUs for applications and minor additions​​.
  • Permits: A building permit is required. Use permits may be needed depending on the project​​.

Before you start

  • Review local zoning regulations and ensure your property is eligible. Prepare a detailed plan for your ADU or JADU that includes design, budget, and adherence to zoning laws.
  • Take a look at your property on Marin Map


  1. Complete the building permit application and submit it along with your plans and a copy of the property deed to the Town​​.
  2. Design your unit with consideration for Fairfax's specific requirements, including plot and floor plans​​.
  3. Undergo a review process with the Ross Valley Fire District (RVFD) and submit reviewed plans back to the town​​.
  4. Complete and record a Deed Restriction, if required, following town approval​​.
  5. Finalize your application by paying any outstanding fees and picking up your building permit​​.

What's next

After receiving your permit, you can begin construction. Post-construction, ensure compliance with all inspections to finalize your project. Consider the impact of your new unit on your property and community, including potential rental income or providing a home for a family member or friend.

Get help

For more detailed guidance, including zoning regulations and specific requirements, visit ADU Laws and Regulations or contact the Planning Department directly.

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