A Denver ADU needs a zoning permit, a building permit and a sewer use and drainage permit (SUDP), plus trade permits, as of October 2026. Denver reviews them together when the first application is complete, so we prepare a full set before we file.
Which permits does a Denver ADU need?
- Construction permits. Zoning, building and the sewer use and drainage permit.
- Trade permits. Electrical, plumbing, mechanical and roofing. Since May 22, 2025, trade permit applications for new construction and additions need an issued residential construction permit before they can proceed.
- Demolition permit. When an old garage or shed comes down first.
- Certificate of occupancy. Nobody can live in the ADU until Denver issues it.
What goes into the design?
- Zoning study. Zone district, neighborhood context, setbacks, height and lot coverage.
- Drawings. Site plan, floor plans, elevations and sections.
- Engineering. Structural design for foundations, framing and snow loads.
- Energy. Insulation, windows and heating sized to the code Denver has adopted.
- Utilities. Sewer route, water service and electrical capacity.
What extra reviews can apply?
A designated landmark or historic district needs a certificate of appropriateness, which Denver recommends securing before zoning and building permits. Parkway lots can need an exception request, and trees in the right-of-way bring in the Office of the City Forester. We spot these in the lot check so they do not surprise you later.
Can Denver deny a qualifying ADU at a hearing?
Not under state law. As of October 2026, Colorado's HB24-1152 requires subject jurisdictions to review ADU applications administratively, without a public hearing, using objective standards rather than judgments about neighborhood character.
Can I just buy permits and build it myself?
Not in Denver. The city says ADUs must be built by a licensed contractor and homeowners cannot apply for ADU permits. We are licensed and insured and hold the permits for your project.