ADU Building, Zoning, and Design Regulations for Modesto, CA

Modesto is a great place to build an ADU and allows you to add significant value to your property. Before you start building, make sure you understand Modesto’s special use regulations for accessory dwelling units.


Zoning and Setback Requirements in Stanislaus County

Zoning Regulations:

  • One main dwelling unit and one accessory dwelling unit and one junior accessory dwelling unit may be allowed on any lot in a residential or mixed use zone where there is only one existing single family dwelling on the lot.
  • No more than two accessory dwellings in a new building detached from the existing buildings may be added to a lot that has an existing multifamily dwelling unit.

Detached ADU Setback Requirements:

  • Front setback must be a minimum of 25 feet.
  • Street side setbacks should be a minimum of 15 feet.
  • Side and rear setbacks should be no less than 4 feet for a one story ADU and 5 feet for two story dwelling units.

Maximum Size

Maximum Area

  • Attached accessory dwelling units: An attached ADU is allowed up to 850 square feet in area for single bedroom units and no more than 1000 square feet for multiple bedroom units.
  • Detached accessory dwelling units: One bedroom detached ADUs are allowed up 850 square feet or up to 1,000 square feet for multiple bedrooms.
  • Junior ADUs: Maximum square footage for JADUs is 500 square feet.

Maximum Height

  • Single story ADUs are limited to a maximum height of 16 feet.
  • Maximum height for 2 story ADUs is 25 feet.

Modesto ADU Rentals

Accessory dwelling units and junior accessory dwelling units in Stanislaus County may only be rented in increments of 30 days or more.


Parking Requirements for ADUs in Modesto

No more than one off-street parking space is required for an ADU in the City of Modesto.

No parking is required for an ADU or junior ADU if:

  • The unit is within 0.5 miles of a transit stop.
  • The ADU is in a district with architectural and historical significance.
  • On-street parking permits are required but not offered to the occupant of the ADU.
View All Modesto ADU Regulations

Custom ADU Builder in Modesto

Backyard Unlimited has helped our Modesto neighbors increase their liveable space and property values by adding accessory dwelling units to their properties.

Over the years, we have worked throughout the greater Modesto area, including Sacramento and Fresno. In addition, our team has installed backyard structures throughout the Central Valley including Stockton and Bakersfield.
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