This guide is intended to provide you an overview of the permitting process for detached accessory dwelling units (ADUs) such as a guest house that are detached from the primary residence and contain provisions for sleeping, cooking, and sanitation.
If there is an existing carriage house (built prior to 1956) or ADU already on your property and you want to add habitable space to it, see the Project Guide for Addition of Habitable Space. Other alterations to ADUs follow the same procedures for inside projects or outside projects for any primary residence.
NOTE: A Certificate of Occupancy is required to complete the permitting process. For information, visit the Building Inspections page.
Before you start your project, you need to know what regulations apply to your property and what factors may impact your project. You'll need to consider:
Historic Landmark Status
Any project that involves changes to the exterior of landmark structures or properties in historic landmark districts must be reviewed by Landmark Preservation staff before you begin. The appropriate zoning, building, curb cut, or revocable permits needed for the project will be issued only after design review has been completed and the project has been approved. To determine your property’s landmark status, use the DevelopDENVER tool to the right. Then, visit the design review web page for more information.
Zoning establishes standards for things such as the size and location of structures and acceptable uses for your property. Before you begin construction, you need to be sure your project is in compliance with the Denver Zoning Code. Use the DevelopDENVER tool to the right to determine the zoning for your property. In the results, click on your zone district for descriptions and definitions; then, click on your neighborhood context for more information on zoning in your area.
Any project that encroaches on a designated parkway setback will need to undergo parkways review. Certain parkways and boulevards are specifically designated by ordinance to preserve their unique character. Each designated parkway has its own right-of-way width and regulations of setback distance of structures and signs. If you are unsure if you live along a designated parkway or for your parkway’s specific regulations, enter your address into the DevelopDENVER tool at right. Look under “Designated Parkways” on the results panel on the left. If a specific parkway appears, click on the “Details” button for information on setbacks.
Denver Building Code provides minimum standards for building in order to safeguard public safety, health and welfare. The permitting and inspection process ensures that all home projects meet these standards and that all dwellings are safe and habitable at the time of construction.
Location of Utilities
When designing your project, you need to know where utilities are located. You cannot build over existing utilities. Before you dig, contact the Utility Notification Center of Colorado at 1-800-922-1987 or 811 to mark underground utilities for your project.
Location of Existing Sewer Lines
If you plan to build a new structure over or within 2 feet of the existing sanitary sewer, you will need to replace the sanitary sewer with approved materials. A plumbing contractor can help you locate the sewer lines on your property. Visit Wastewater Sewer Use and Drainage Permit (SUDP) for application, guidelines and other specific information. Contact the Department of Public Works at 303-446-3759 for additional details.
NOTE: Wastewater Management defines an ADU as any structure that has either a bathroom or kitchen or is used as habitable living space.
Location of Existing Water Service Lines
Denver Water will evaluate your existing water service line to ensure it will support the addition of an ADU. Visit Denver Water for licensing and fees. Contact Denver Water Sales Administration at 303-628-6100 for additional details.
Transportation review and approval is needed if you are changing the location of any driveways that connect to public streets or proposing improvements, such as changing the curb cut, within the “right of way” (ROW), which includes public streets and sidewalks. All ROW projects must be performed by a licensed contractor and in full compliance with the City Charter, ordinances, permitting processes and all other applicable standards, specifications and requirements. Licensed contractors can obtain ROW permits at Public Works Permit Operations, 2000 West 3rd Avenue, or directly from the ROW inspector at (303) 446-3469. NOTE: Alterations to a driveway that connects to an alley, instead of a public street or sidewalk, do not require transportation review.
Listed in the order they must be obtained. All permits must be in hand and at site before work may begin.
The above must be in hand before you apply for the following:
*For a complete list of required documentation for zoning and building plan review, including minimum submittal requirements, download the Residential Permitting Guide (PDF). Zoning and/or building permit applications for logged-in residential projects will only be accepted if minimum submittal requirements are met.
Quick Permits may be applied for by email. See www.DenverGov.org/QuickPermits. For same day service, sign in online or at the kiosk once for two Quick Permits at a time.
Sign in online or at the kiosk once for zoning review and #1R permit (Log in).
Zoning and Building permit fees are based on valuation of the work to be completed including the labor and materials.
For sewer use and drainage permits, there is a $100 application fee, plus appropriate fees shown on the current permit fee schedules (see "Public Works / SUDP") based upon the use of the accessory dwelling unit. The fees change yearly. Fees for sewer use and drainage permits will depend on whether or not your property is eligible for tap credits (usually applies when you have an existing tap). Exact fees and credits are calculated during the permit review.
There are no fees for Transportation, Parkways or Landmark review.
ROW permit fees are based on the amount of work constructed and the amount of time they are occupying the ROW.
Fees can be paid in person at our cashier on the 2nd floor of the Wellington Webb Building. We accept Visa, MasterCard and Discover Card, cash and personal checks at our counter.
All approved construction set of documents, permits and inspector signature card are to be available on site upon request.
Typical inspections during construction of accessory dwelling units include the following:
NOTE: The inspections listed above may vary depending on the complexity of your project. You will be advised as to which inspections your project requires through the permitting process and by your inspector.
Decide whether you plan to complete the project yourself or hire a licensed contractor to complete the job for you.
Do It Yourself
You may need to pass a Home owners exam to demonstrate proficiency in specific trades in order to get a permit to do the work yourself.
You will also need to meet a set of requirements established by the Denver Building Code and the Building Department Policy ADMIN 131.3 governing homeowner completed work. This policy can be found on our Building Codes, Forms and Policies page.
Use the Contractor license search to see if your contractor has obtained a contractor's license from the City and County of Denver.
To view other considerations, see our Doing the Work Yourself page.
Every project is different. Depending upon the complexity of your project, the permit requirements and inspection process may vary from the information presented in this guide. If you have any questions, please contact us.