Citywide Accessory Dwelling Units (ADUs)

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As part of the city’s ongoing effort to expand housing availability and choice, the city has launched the Citywide ADUs project. Following recommendations from Blueprint Denver, the city's land use and transportation plan, this project will look at potential updates to the Denver Zoning Code, zoning map, and Former Chapter 59 zoning to allow accessory dwelling units (ADUs) in all residential areas of the city.

The project builds upon the ADUs in Denver project, which updated building standards for ADUs to make them better fit in different neighborhoods. Prior to those code changes, the zoning code considered ADUs through a one-size-fits-all approach with little variation by neighborhood. Now, each zone district has specific design standards for ADUs related to setbacks, building height, bulk plane and other design requirements, which must be met for an ADU to be constructed.  

This proposed zoning code text amendment is sponsored by Councilmembers Sarah Parady (at-large), Chris Hinds (District 10) and Darrell Watson (District 9), in partnership with the Department of Community Planning and Development and Mayor Mike Johnston. It will be complemented by a proposed zoning code map amendment that will ensure properties are rezoned to reflect the goals of the text amendment. The proposal is expected to go to City Council for a vote this fall.  

Examples of attached and detached ADUs

What is an "ADU"?

Accessory dwelling units, or ADUs, are self-contained, smaller living spaces that are an extension of an existing property. They are often called mother-in-law suites, granny flats, casitas, backyard cottages, garage apartments or basement apartments. An ADU has its own kitchen, bath and sleeping area, but is not considered a separate property that could be sold on its own. 

Learn more about these living spaces 

See if your property is zoned to allow an ADU

What about ADUs in Metro Districts or Homeowners Associations (HOAs)?

The City and County of Denver does not regulate homeowners associations (HOA), or review permit applications to HOA regulations. If you live in a metro district, homeowners association, or similar, be sure to check the bylaws for that organization to ensure your project is allowed under their local rules. 

About Accessory Dwelling Units

As cities grow and change, the way people live changes too. Many people want a separate space where elderly parents or kids living at home can still have independence, a space that can be rented out to generate income, or just to rent a smaller, more affordable space. Accessory Dwelling Units, or ADUs, are a low-impact way to meet these needs and expand housing options for people of all ages.

ADUs are self-contained, smaller living spaces that are an extension of an existing property. They are often called mother-in-law suites, granny flats, casitas, backyard cottages, garage apartments or basement apartments. An ADU has its own kitchen, bath and sleeping area, but is not considered a separate property that could be sold on its own.  

See if your property is zoned to allow an ADU

Constructing Accessory Dwelling Units(PDF, 517KB)

Scroll down for...

  • the History of ADUs,
  • ADUs Today,
  • the Facts on ADUs in Denver, and
  • Additional Resources.

History of ADUs

Accessory dwelling units have long been part of the fabric of Denver, and many other cities around the U.S. Pictured below is the Grant Street Mansion, built in 1892 with an adjacent carriage house. Much like the design of ADUs today, the carriage home provided living quarters above an area for storing a horse-drawn carriage. Historic carriage homes still exist in many older Denver neighborhoods, including Baker, Capitol Hill, Curtis Park, City Park West, Congress Park, Cole, Whittier, Speer, Country Club, West Washington Park, and Platt Park.

Left: Grant Street Mansion circa 1892 (credit Denver Public Library)
Right: Grant Street Mansion circa 2021

Historic Grant Street Mansion in the Capitol Hill neighborhood (credit: Denver Public Library) The Grant Street Mansion and carriage house today

ADUs Today

Today's ADUs take many forms. They can be built as a free-standing structure in the backyard, could be built above a garage, could be an addition built onto the main home, or could be a converted space within the main home, such as an attic or a basement. The choice of how and where to build an ADU will depend on the property owner's needs and construction budget as well as zoning and building codes. 

Instagram icon  Explore more ADU styles from around the world >

The Facts on ADUs in Denver

  • The Denver Zoning Code regulates height, overall size, setbacks, and more. This zoning code project will look at how these standards impact ADUs.
  • An ADU must look “compatible” with the main house. It must be smaller than the zoning allowance for the main house and fit in with the neighborhood. This project will improve how ADUs fit in with different neighborhoods and block patterns.
  • In single unit zone districts, the owner of the property MUST live on the property, either in the ADU or in the main house.
  • This project will improve how ADUs fit in with different neighborhoods and block patterns. It will not change what uses are allowed in single-unit zone districts.
  • All ADUs are reviewed according to the Denver Building and Fire Code to ensure structures are safe and can be accessed by first responders.

Additional Resources

AARP: The ABCs of ADUs - A guide to accessory dwelling units

AARP Livable Communities: ADU 'Hot Topics'

5280 Magazine's Guide to Building an ADU

American Planning Association's ADU Collection - Policy guidance from around the country 

ADUs in Denver Project Archive

The zoning code changes resulting from the ADUs in Denver project went into effect on July 5, 2023. The purpose of the project was to remove barriers to building ADUs and to ensure they fit into different neighborhoods. Prior to these zoning code changes, there was a one-size-fits-all approach to ADU design with little variation by neighborhood. Learn more about the ADUs in Denver project, read project documents, and watch meeting recordings in the sections below.

Zoning Code Update Summary

After more than a year working with a community advisory committee, technical experts, neighborhood organizations, City Council members, and the general public to develop zoning code changes for accessory dwelling units (ADUs), Denver’s Department of Community Planning and Development announced the passage of these changes by Denver City Council on Monday, June 5. The zoning changes will go into effect on Wednesday, July 5 and apply to ADU applications received after June 30.

Prior to these zoning code changes, there was a one-size-fits-all approach to ADU design with little variation by neighborhood. The changes allow for nuance based on neighborhood context, and include some of the following updates:

  • There is more flexibility to create two-story ADUs in Denver’s more urban areas, making construction more cost effective than the prior 1.5-story height limit.
  • In suburban neighborhoods, ADUs will generally be one-story, with rear and side setbacks (the distance from the ADU to the rear and side lot lines) based on neighborhood design.
  • The building lot coverage exemption in place for vehicle parking is extended to ADUs, making building one-story ADUs easier. One-story ADUs can better serve occupants who are elderly or disabled.
  • In more urban neighborhoods, dormers (vertical windows that rise from a sloping roof) may be allowed to extend past the bulk plane, which is the space a building is allowed to occupy on the lot. Dormers can allow ADUs to better match the architectural features of a neighborhood.
  • Zoning barriers that previously limited the conversion of existing structures like garages into ADUs have been removed.
  • The maximum floor area of ADUs for smaller lots is increased, allowing these lots the option of building ADUs that can serve a family. This can keep multi-generational families on the same property.

Read the Strategy Report(PDF, 22MB)

Read a 2-page Summary of the Recommendations(PDF, 2MB)

Read the Denver Zoning Code Amendment(PDF, 18MB)

Read the Former Chapter 59 Bridge Amendment(PDF, 64KB)

Learn how community engagement was performed 

Scope and Timeline

ADU Project Schedule

The foundation for this project was Blueprint Denver, a citywide land use plan that was adopted by Denver City Council in 2019 after three years of public outreach. Thousands of residents helped create the policy recommendations in Blueprint Denver, which included these recommendations for ADUs:

  • that barriers to ADU construction be removed, 
  • that zoning rules be reviewed and adjusted so ADUs fit into a variety of neighborhood contexts.


This project aimed to implement the Blueprint Denver recommendations through a community-driven update to the Denver Zoning Code. The project did not change where in the city ADUs are allowed, but looked at how they are designed, how they fit in with different types of neighborhoods and block patterns, and how updates to the zoning code could reduce barriers to creating ADUs.

Read more in the Project Background Report(PDF, 3MB)

Read more in the Issues Identification Report(PDF, 4MB)

Read more in the Alternatives Report(PDF, 3MB)


City planners worked with residents to develop the specific language for new ADU zoning standards. This work included public workshops, small focus groups, and surveys to...

  1. explore the challenges residents currently face in constructing an ADU,
  2. evaluate possible alternatives for resolving these challenges while achieving the project's goals of reducing barriers and improving design outcomes,
  3. work with residents and the Community Advisory Committee to recommend a particular strategy, and
  4. develop and write the zoning standards.

Adoption process: Both the Denver Planning Board and Denver City Council voted in favor of adopting the new text into the Denver Zoning Code. 

Community Advisory Committee and Project Team

Updating the zoning code is a collaborative, community-driven process facilitated by an independent consultant working with city staff and guided by an advisory committee of residents, local businesses, neighborhood groups, community-serving organizations and other constituencies from across Denver.

Community Advisory Committee

A key element of the project's outreach plan is the community advisory committee. The committee provided input on key issues, challenges and opportunities, as well as on proposed alternatives. The input was considered by city staff and summarized in the city’s final Strategy Report to City Council. 

Committee members were selected from more than 80 community members who submitted the interest form. The committee includes people from across Denver with experience from different neighborhoods and housing types. Some committee members have specific expertise in ADU design/construction, real estate, historic preservation and/or affordable housing.

View committee selection criteria(PDF, 101KB).

View committee charter(PDF, 260KB).

See Project Archive for summaries of previous committee meetings.


Neighborhood, organizations, and other affiliations

Councilwoman Kendra Black

Is the Denver City Council Member for District 4.

Councilman Chris Herndon

Is the Denver City Council Member for District 8.

Gabriel Calderon

A Berkeley resident and a member of BRUN-Berkeley Regis United Neighbors RNO.

Ozi Friedrich

A Baker resident, architect, chair of the Baker Landmark Committee, and a member of the Baker Zoning Committee.

Emily Goodman

A Community Navigator for East Colfax Community Collective.

Naomi Grunditz

A Clayton resident, planner and aide for Council District 1.

Mary C Hawthorne

A Wellshire resident and member of Cherry Hills Heights HOA.

Chelsey Hume

A Virginia Village resident and an ADU project manager for Habitat for Humanity of Metro Denver.

Lisa Kerin-Welch

A Mayfair-Montclair resident, real-estate advisor for ADU4U and a member of STRAC-Denver’s Short-Term Rental Advisory Committee.

Pamela Jiner

A Montbello resident and director of Monbello Walks/Montbello 2020.

Jennifer Steffel Johnson

A Park Hill resident and CU Denver Professor of Planning.

Rosemary Stoffel

A University Park resident, board member of University Park Community Council, concerned with design review and short-term rentals.

Shawn Johnson

A Sunnyside Resident who has met barriers in building a fully accessible ADU for his aging mother.

Gosia Kung

A Sloan Lake resident, architect, and Denver Planning Board Member.

Terra Mazzeo

A City Park West resident, architect and owner of AlleyFlats, an ADU prefabrication/development company.

Brooke Murphy

A La Alma-Lincoln Park resident and a planner/impact associate for Elevation Land Trust.

Cesar Olivas

A Chaffee Park resident and an Architect working closely on affordable housing projects in Denver and throughout the rocky mountain region.

Donna Repp

A Mar Lee resident and past president of the Mar Lee/Brentwood/Sharon Park Neighborhood Association

Suzanne Reede

A Regis resident concerned with housing options and short-term rentals near the university.

Sarah Senderhauf

A Park Hill resident and ADU sales manager/real-estate broker with L&D Construction.

Renee Martinez Stone

A West Highlands resident and Executive Director of WDRC-West Denver Renaissance Collaborative.

Michelle Ferrigno Warren

An Athmar Park resident and Athmar Zoning Committee member.

Darcy Wilson

A Cole resident, construction professional for Stan Mar, and a member of the African-American Construction Council and UNDR – United Neighbors of NE Denver.


Project Team

Josh Palmeri 
Senior City Planner – Project Manager 

Libby Kaiser 
Senior City Planner 

Fran Peñafiel - Habla español 
Associate City Planner 

Abe Barge 
Principal City Planner 

Consultants and Partner Agencies


Advisory Committee Meetings

Advisory Committee #1
4:30-6:30 p.m., Thursday, March 3, 2022
Virtual meeting via Zoom

Advisory Committee #2
4:30-6:30 p.m., Thursday, April 7, 2022
Virtual meeting via Zoom

Advisory Committee Meeting #3
4:30 - 6:30 p.m., Thursday, May 5, 2022
Virtual meeting via Zoom

Advisory Committee Meeting #4
4:30-6:30 p.m., Thursday, June 9, 2022
Virtual meeting via Zoom

Advisory Committee Meeting #5
4:30 - 6:30 p.m., Thursday, August 4, 2022
Virtual meeting via Zoom 

Advisory Committee Meeting #6
4:30 - 6:30 p.m., Thursday, September 8
Virtual meeting via Zoom

Advisory Committee Meeting #7
4:30 - 6:30 p.m., Thursday, November 3
Virtual meeting via Zoom

Advisory Committee Meeting #8
4:30 - 6:30 p.m., Thursday, December 15
Virtual meeting via Zoom 

Focus Groups

Suburban Focus Group
5 - 6:30 p.m., June 16, 2022
Virtual meeting via Zoom

Architects, Designers, and Builders Focus Group
5 - 7 p.m., July 27, 2022
Virtual meeting via Zoom

Urban Edge Focus Group
4 - 6:30 p.m., October 19, 2022
Virtual meeting via Zoom

Suburban II Focus Group
4:30 - 6 p.m., October 26, 2022
Virtual meeting via Zoom

Community Meetings & Engagement Summaries

Outreach and Feedback Summary for Phases 1-3 (January 2022-November 2022)(PDF, 615KB)

Outreach and Feedback Summary for Phase 4 (November 2022-February 2023)(PDF, 592KB)

Outreach and Feedback Summary for Phase 5 (February 2023 - March 2023)(PDF, 321KB)

Outreach and Feedback Summary for Phase 6 (March 2023 - May 2023)(PDF, 432KB)

ADUs in Denver Online Survey
Available May 4 - 31, 2022

ADUs in Denver Open House
4:45 - 7:15 p.m., Thursday, August 25, 2022
Carla Madison Recreation Center
2401 E. Colfax Ave., 
Denver, CO 80206
And online August 26 - September 16

Open House
Swansea Recreation Center
5 - 7 p.m., Wednesday, January 25, 2023
2650 E 49th Ave
Denver, CO 80216

Open House
La Alma Recreation Center
5 - 7 p.m., Thursday, January 26, 2023
1325 W 11th Ave
Denver, CO 80204 

Office Hours (Virtual OR In-Person)
Various times, Monday, January 30 - Thursday, February 2, 2023
In-Person at the Wellington E. Webb Municipal Office Building 
201 W Colfax Avenue
Denver, CO 80202

Open House
Montbello Recreation Center
5 - 7 p.m., Wednesday, February 1, 2023
15555 E 53rd Ave
Denver, CO 80239

Open House 
Virginia Village Branch Library
3:45 - 5:45 p.m., Thursday, February 2, 2023
1500 S Dahlia St
Denver, CO 80222

Open House - Virtual
5 - 6:30 p.m., Tuesday, February 7, 2023
Virtual meeting via Zoom

Open House
Bear Valley Branch Public Library 
3:30 - 5:30 p.m., Thursday, February 9, 2023
5171 W Dartmouth Ave
Denver, CO 80236

Planning Board Hearing
3 p.m., Wednesday, April 5, 2023

City Council LUTI Committee
10:30 a.m., Tuesday, April 18, 2023 

Office Hours: Bridge Amendment
4 - 7 p.m., Monday, May 15, 2023
Green Valley Ranch Recreation Center
4890 Argonne Way
Denver, CO 80249

Office Hours: Bridge Amendment
12 - 2 p.m., Wednesday, May 17, 2023
Green Valley Ranch Library
4856 Andes Ct.
Denver, CO 80249

Denver City Council Public Hearing
5:30 p.m., Monday, June 5, 2023