Skip navigation

Project Guide for Detached Dwelling Units

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.

Help Me Get Started . . .

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.

Building Code

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.

  1. Current City of Denver Contractor’s License Affidavit of Requirements for Owner-Occupier Permits (see Issuance of Owner-Occupier Permits (PDF) for more information).
  2. Landmark Certificate of Appropriateness – if the project is in a designated historic district or landmark property. Visit the Design Review web page for more information.
  3. Forestry Review – required if your project will impact the canopy or roots of street trees. Contact Denver Forestry by email ( or by phone at 720-913-0651 to evaluate your project and visit the Denver Forestry web page for additional information. Allow about 3 to 5 business working days for inspections and approval.
  4. Parkways Review – if your property is along a designated parkway and the project encroaches on the parkway setback
    You will need: A completed Parkway Exception Request form and a site plan that includes property lines, parkway setback from property line, proposed type, location and dimensions of encroachment into parkway setback, location of existing residence on property and labeled streets. To get a copy of the form and additional information, contact
  5. Transportation Review - required if there are proposed improvements in the Right-of-Way associated with this ADU or if there is a new or modified driveway connection to the street
    You will need: A site plan that includes the location of the existing and proposed driveways; dimensions from the driveway to the property line and any adjacent driveways; width of driveway; and material used in construction. Find the city transportation engineer assigned to your area using the DevelopDENVER tool at right and contact him/her for more information.
    NOTE: If the proposed driveway connects to a State Highway then CDOT access permits and a Transportation Engineering Plan will be required. For questions about the driveway location, Transportation Engineering Plan, or CDOT access permit requirements, please contact your Site Engineering Transportation Engineer using the DevelopDENVER property tool to the right. 
  6. Adjacent Property Owner Notification
    Building permit applicant must submit either a return receipt of certified mail delivery or a signed receipt of personal notification for all adjacent properties at the time of permit application and plan submission at permit counter. A permit will not be issued until 10 working days after adjacent property owners were notified. 
  7. Zoning Use Permit (Commercial Zoning) – If you are changing the use of the structure and/or adding a dwelling unit, staff must first determine what is permitted under your current zoning.

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.

  1. Zoning Review*
  2. #1R Building Permit (Log In)*
  3. Wastewater Sewer Use and Drainage Permit (SUDP) (Log In or Plan Review)
    Visit the wastewater permits page for application, complete submittal requirements and guidelines, and other information.
  4. Address Assignment Card
  5. #11 Forced-Air Furnaces, Ventilation and Air Conditioning and Gas Piping Permit (Quick Permit) - required for new ductwork
  6. #4 Plumbing Permit (Quick permit) - required for new or relocated plumbing fixtures
  7. #3 Electrical Permit (Quick permit) - required for new or relocated electrical outlets or light fixtures
  8. #2 Roofing Permit (Quick Permit), including information on the number and type of shingles
  9. Right of way (ROW) Construction Permit – required for all work located in the ROW, which must be performed by a licensed contractor. Contractors can obtain the ROW permits at Public Works Permit Operations, 2000 West 3rd Avenue or directly from the ROW inspector at (303) 446-3469. NOTE: If significant improvements within the ROW are being proposed, you will need a transportation plan. Find your transportation engineer using the DevelopDENVER tool at right and contact him/her for more information.

SUDP application and materials may be submitted online through e-permits or by email (

Quick Permits may be applied for by email. See 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). 


Estimate Fees
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. 

Pay Fees
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.

To pay by mail, send check to:
Development Services
Wellington Webb Municipal Building
201 W. Colfax Ave., 2nd Floor
Denver, Colorado 80202

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:



  • Pre Construction Meeting
  • Temporary Service 
  • UFER
  • Footing
  • Foundation Wall and Foundation Perimeter Drain
  • Waterproofing
  • Frost Wall Insulation
  • Water Service
  • Underground Utilities (Electrical, Mechanical, Plumbing)
  • Setbacks
  • Bulk Plane Inspection
  • Exterior Sheathing
  • Rough Utilities (Electrical, Mechanical, Plumbing)
  • Frame
  • Roofing
  • Exterior Lath
  • Insulation (Batt and Blown)
  • Drywall
  • Blown Insulation
  • Pressure Test 
  • Final Utilities (Electrical, Mechanical, Plumbing) 
  • Temporary Certificate of Occupancy
  • Certificate of Occupancy
  • Final construction inspection
  • Zoning inspection


Wastewater Inspections:  

  • Wastewater inspection for new, replaced, or rerouted sanitary sewer
  • Wastewater review for storm sewer/drainage work as called out on permit
  • If construction occurs in a floodplain, additional inspections are required.
  • Wastewater final inspection - consists of inspection of the 2-way cleanouts and all storm sewer work and storm drainage from grading, downspouts, and storm work
  • Only a licensed contractor can call for an inspection.


For Right-of-Way:

  • Construction Engineering will inspect work performed in the ROW and check to see if ROW infrastructure was damaged during construction.


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.

  • Please be aware that the ROW inspector may require the replacement of any damaged infrastructure (i.e. sidewalk and curb and gutter) in the ROW adjacent to your site. 
  • Section 49-551.1 of the Denver Municipal Code states that the property owner or lessee of any real property is responsible for the continuing care, maintenance, repair, and replacement of all improvements installed in the public ROW between the property line and the curb line adjoining their property.
  • Please take care not to damage the ROW infrastructure during the construction.

Who Will Be Doing the Work?

Decide whether you plan to complete the project yourself or hire a licensed contractor to complete the job for you.

Do It Yourself

Do-It-YourselfYou 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. 


Contractors 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.

Home Projects

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.


What you need to know for your project!

Enter your property address or street intersection:
View property details including zoning, landmark status, inspector districts and more.