Accessory Dwelling Units

adu concept stone siding

Your Accessory Dwelling Unit (ADU) From Start to Finish

The steps for permitting your Accessory Dwelling Unit (ADU) with the City of Modesto are outlined below in eight steps. Click through the tabs below for a walk through of the process.

  1. 1. Create a Plan

Create a Plan

The first step is to create a Site Plan which shows your property boundaries, placement and size of:

  • Existing House
  • All Structures (Detached garage, gazebo and any others)

Plan Options

Stanislaus County in partnership with the cities of Ceres, Modesto, Oakdale, Riverbank, Turlock, and Waterford have developed seven (7) different ADU plans for detached new construction, each with multiple options for exterior finishes, available free to property owners.

260 Square Foot ADU Model 1 Elevation and Floor Plan

Engineering Plan Documents Available on Request

Each of the pre-approved ADU plans has engineering documents including 2022 Codes, Structural Calculations, and Title 24 energy calculations.  These files are provided on request to download in ZIP file format due to their size. 

Request ADU Engineering File Sets (ZIP)

  1. 2. Get Planning Advice from the City of Modesto
  1. 3. Prepare Permit Submittal Package
  1. 4. Apply for your ADU Permit
  1. 5. Hire Experienced, Licensed Professionals
  1. 6. Your Plans will be reviewed by City Staff
  1. 7. Permit Issued
  1. 8. Construct Your ADU, Schedule and Pass Inspections

Additional ADU Resources

Local Assistance

CalHFA ADU Grant Program

San Joaquin Valley Regional Planning Agencies Policy Council (REAP)

  • Informational ADU Handout for the General Public
  • Free ADU Housing Plans, and more

California Housing and Community Development Department (HCD)

  • Overview of ADU funding programs, current laws, HCD’s ADU Handbook and other ADU resources and information.

White House Briefing - Housing Costs