Accessory Dwelling Units

Accessory Dwelling Unit (ADU) & Junior Accessory Dwelling Unit (JADU) Information

In December 2021, the Tustin City Council adopted Ordinance No. 1517 amending Tustin City Code 9279 which brought Tustin's City Code into compliance with State law pertaining to Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs). 

Interested in adding an ADU or JADU to your property? This page will provide you with helpful definitions, FAQs, and resources to get started.


  • Difference between an ADU & JADU: ADUs and JADUs are both independent living units, which are allowed at a minimum size of 220 square feet, and function as accessory to a primary residential use on a property with an exterior entrance into the unit.   While ADUs and JADUs have similarities, there are some key differences. 
    •  ADUs: An “Accessory Dwelling Unit” or “ADU” is an attached or a detached residential dwelling unit which provides complete independent living facilities for one (1) or more persons. An ADU includes permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as a single-family or multi-family dwelling and can be up to 850 square feet in size for a studio or 1-bedroom ADU, and up to 1,200 square feet for a unit with two (2) or moreADU Graphic bedrooms.

    • JADUs: A "Junior Accessory Dwelling Unit” or “JADU” is a unit that is no more than 500 square feet in size and contained entirely within the walls of a proposed or existing single-family residence, including attached garages.  A JADU may include separate sanitation facilities or may share sanitation facilities with the single-family residence.

  • Types of ADUs: There are three types of ADUs, defined below.  

    • ADU, Attached: is an ADU, other than a Converted ADU, that is physically attached to a primary dwelling.

    • ADU, Converted or “Converted ADU”: is an ADU that is constructed within all or a portion of the permitted existing interior space of an accessory structure or within a portion of the permitted existing interior space of a dwelling structure, including bedrooms, attached garages, storage areas, or similar uses.  A Converted ADU also includes an ADU that is constructed in the same location and to the same dimensions as a permitted existing structure or portion of a permitted existing structure.

    • ADU, Detached: is an ADU, other than a Converted ADU, that is physically separated from, but located on the same lot as, a primary dwelling structure. 
  • Setback: A setback is a certain required distance from a property line to the exterior of a building wall that must remain clear and free of any structures.   The setback is generally measured from the property line to the exterior side of a building wall closest to the property line. Setbacks are generally measured as front, side, or rear yard setbacks.


Read the ADU/JADU Ordinance No. 1517 by clicking here, or view the full TCC 9279 by clicking here

For more information about ADUs and JADUs, please follow these links:

Questions? Contact the Planning Division by phone, e-mail, or in person at the following: 
(714) 573-3140 | | Tustin City Hall located at 300 Centennial Way, Tustin, CA 92780

We are available for both virtual and in-person assistance on Monday - Thursday from 7:30 a.m. - 5:30 p.m., and on Friday from 8:00 a.m. - 5:00 p.m.