Accessory Dwelling Units Code Amendment

Accessory Dwelling Units proposal

A proposal to allow Accessory Dwelling Units in Tucson has been developed based on input from the public and a stakeholder group and is currently going through public review.

The current draft proposal would allow:

  • One ADU to be built on any residential lot in the city (meaning a lot with one or two homes)
  • The maximum size of the ADU would be 1,000 square feet for lots over 7,000 square feet and 750 square feet on lots under 7,000 square feet
  • All other dimensional standards, including maximum building height, lot coverage, and setbacks would apply
  • One parking space would be required per ADU, which could be waived for sites that are a quarter-mile from transit or a bike boulevard; on-street parking can also be used
  • Each newly constructed ADU would be required to have a cool roof

Learn more: take a look at this flyer for an overview of the proposal (folleto en Español).

Have questions related to ADUs? Check out our ADU Frequently Asked Questions here.

Share your feedback!  Please use this survey to share your thoughts on the ADU proposal. Encuesta en Español

Watch a video to see examples of casitas in Tucson and learn more about the proposal!

Additional information and reference materials related to the ADU project 

Past Meeting Materials | What is an ADU? | FAQ | Press Related to the ADU Project | Reference Materials on ADUs

Planning Commission recommends approval of Accessory Dwelling Units Code Amendment after Public Hearing

The Planning Commission held a virtual public hearing on Wednesday, September 15 at 6pm to take additional public comment related to the proposed amendment to the Unified Development Code to allow ADUs. After hearing from seventeen speakers, and receiving over 100 written comments, the Commission voted 9-0 to recommend the proposal as presented by staff, with additional recommendations to Mayor and Council to develop programs to provide resources and technical support to make ADUs more affordable, and evaluate the program in 24 months. Watch a recording of the meeting here:


On Wednesday, July 28, 2021, the Planning Commission held a public hearing on the proposed amendment to the Unified Development Code to allow ADUs. Staff presented the draft proposal and an overview of the process to date for the Planning Commission to review and discuss. At that meeting, the Planning Commission voted 10-0 to continue the public hearing until Wednesday, September 15, 2021 at 6 pm, to allow for the public to have additional opportunity to comment on the ADU proposal. 

The following is a video recording of that meeting:

The meeting agenda and materials can be found on the Planning Commission webpage.

The presentation from that meeting may be found here.

Planning Commission Study Session on Accessory Dwelling Units

The City of Tucson Planning Commission held a study session on the proposed amendment to the Unified Development Code to allow ADUs on Wednesday, June 30 at 6 pm. Staff presented the draft proposal and an overview of the process to date for the Planning Commission to review and discuss. At that meeting, the Planning Commission voted 9-0 to set a date of Wednesday, July 28 at 6 pm, for a Public Hearing to provide the public an opportunity to comment on the ADU proposal. 

The following is the video recording of that meeting:

The meeting agenda, & materials can be found on the Planning Commission webpage.

The presentation from that meeting may be found here.

Public Meetings: Accessory Dwelling Units Code Amendment Draft Proposal
What could these housing options mean for Tucson?

The City of Tucson Planning and Development Services Department recently held a series of virtual public meetings to share a proposed code change to allow backyard casitas (also known as Accessory Dwelling Units) in Tucson. Attendees heard how this housing option can provide affordable housing, help seniors age in place, and promote sustainable infill development. 

Staff presented a draft proposal for new zoning regulations to permit this housing type. This proposal was developed based on what we heard at public meetings held earlier this year, and input from a stakeholder group representing a range of viewpoints and expertise. Participants had a chance to share feedback and hear from other community members.

Watch a recording of one of the meetings here:


Public Meetings to Gather Community Input

The first round of public meetings were held on February 24 and 25 for members of the public to learn more about how Accessory Dwelling Units can provide additional housing options in Tucson, how they are regulated today, and what changes are being considered in order to make this housing option more accessible. Participants also had a chance to share their thoughts and feedback. Additional meetings will be held later in the spring to share a draft proposal that will be developed based on the public input.

View meeting video


On Tuesday, November 17, 2020, Mayor and Council directed Planning and Development Services to begin the process of amending the Unified Development code to define and permit Accessory Dwelling Units (aka casitas), identify the zones where they are appropriate and create development standards regulating unit size, height, minimum lot size, maximum lot coverage, setbacks, parking requirements and other relevant aspects​ in order to promote this affordable housing option in a manner that is compatible with existing neighborhoods. This process will involve extensive public outreach and engagement. Follow the process here to learn how to get involved.

View the presentation that was shared with Mayor and Council here.

What is an Accessory Dwelling Unit?

  • An Accessory Dwelling Unit is an independent housing unit with its own kitchen, bathroom, living and sleeping space. These units are typically under 1,000 square feet and are accessory to a primary residence.  

  • ADUs can be detached, attached or interior to the primary residence (i.e. through the conversion of a garage, basement or attic). These units are often referred to as casitas, mother-in-law units or granny flats, among other terms.  

ADU examples

Image courtesy of AARP, The ABCs of ADUs

What are the Benefits?

Accessory Dwelling Units have many benefits. This housing style can be a means to:  

  • Increase the supply of affordable rental housing  
  • Encourage more flexible housing options for seniors  
  • Support multi-generational households and living arrangements  
  • Provide supplemental income to landowners and promote neighborhood stability​  
  • Support climate-resilient infill development in context with existing neighborhoods  

In the past decade, many cities have taken steps to legalize ADUs as a way to add to their affordable housing stock and meet other community goals. Some states have even enacted legislation to make this housing option available statewide, including California, Oregon and New Hampshire. 

Why are ADUs being considered in Tucson?

This proposed code amendment stems from and supports ongoing analysis and policy recommendations related to housing needs and sustainability goals in our community.  

  • The City of Tucson has been working with Pima County on a Housing Study to understand our local housing market and identify gaps in our housing stock. Initial findings show that over half of renter households and over 22% of homeowner households are housing cost burdened, meaning they spend more than 30% of household income on housing costs (i.e. rent, mortgage, property tax, utilities).  ADUs can often be an affordable housing option. As a smaller living space, the cost of renting an ADU can be lower than that of a larger apartment. Additionally, adding to the overall supply of housing across the city tends to promote stable rent levels.  

  • On June 9, 2020, Mayor and Council directed staff to form a Commission on Equitable Housing and Development. This Commission has been tasked with providing advice to the Mayor and Council on topics such as: how the City can increase city investment in housing; how to preserve affordability while increasing housing production/ stock; and how to protect barrios and communities from rapid change and displacement.  

  • On September 9, 2020, Mayor and Council adopted a Climate Emergency Declaration calling for carbon neutrality by 2030 and the development of climate adaptation and mitigation strategies. ADUs can be an important tool to support compatible residential infill development. ADUs represent an efficient use of existing infrastructure by adding new housing in already developed areas. As a smaller footprint housing option, ADUs are typically energy efficient structures. Furthermore, these units are often developed in central neighborhoods with multi-modal transportation options. ADUs are an important means to retrofit our neighborhoods to be more climate-resilient.  

  • The Age Friendly Tucson Action Plan was adopted by Mayor and Council in May 2019. Goals of this plan include providing affordable housing options for older adults and to facilitate older adults and people with disabilities aging in place. ADUs are a way to support  these goals, as they can be an affordable option for seniors, and also support aging in place and aging in proximity to family and caregivers.  

How are ADUs currently regulated in Tucson?

  • “Accessory dwelling unit” is not a defined term in the Unified Development Code (UDC). In fact, the code currently states that accessory structures within residential zones may not be a dwelling unit.  

  • Accessory sleeping quarters/guest house are allowed, provided other regulations are met, however, a full kitchen in the unit is not permitted, as sleeping quarters are not intended to be a self-contained unit.  

  • A second dwelling unit is allowed in certain districts, depending on the lot size and ability to meet other zoning regulations. Minimum lot size requirements and density regulations make it difficult to develop ADUs on most standard size lots in urban residential districts.  

What comes next and how can I get involved?

We will be holding a series of public meetings beginning in early 2021 to share information about this proposal and get input from the public. Watch this page or subscribe to the PDSD newsletter to stay informed!

Past Public Meeting Materials

Meeting Type Presentation Meeting Notes Link to Video
Planning Commission Public Hearing - July 28, 2021 Click here

Planning Commission Materials

Legal Action Report

Planning Commission Study Session - June 30, 2021 Click here

Planning Commission Materials

Legal Action Report

2nd Public Hearing - May 19, 22, 24 & 25,2021  Click here Meeting Summary
1st Public Hearing - February 24 & 25, 2021 Click here Meeting Summary

Press Related to the ADU project



Newspaper / Magazines


Reference Materials on ADUs