Denver allows ADUs in all zone districts that allow new single-unit dwellings. California state ADU law does not apply here. Check the city ADU map before you design; some lots still need a rezoning.[1]
What is an ADU? An accessory dwelling unit is a small second home on the same lot as the main house: a backyard unit, garage conversion, attached addition or guest house with its own kitchen and bath.
| Size limits | Maximum detached ADU gross floor area: 864 sq ft on zone lots of 7,000 sq ft or less, and 1,000 sq ft on larger lots.[2] |
|---|---|
| Height | District-specific. Example from the city overview: in the Urban Neighborhood Context, ADUs are limited to two stories and 24 ft. Confirm your district in the Denver Zoning Code.[2] |
| Setbacks | Detached ADUs must sit in the rear 35% of the zone lot and meet district side, rear, bulk-plane and lot-coverage rules. Vehicle access must come from an existing alley when one is present.[2] |
| Parking | Not verified. We did not find this on the official pages we checked. Ask the city before you design. |
| Owner occupancy | In single-unit zone districts, the property owner must live in the main house when applying for permits to build an ADU. That is not required when the main house and ADU are built at the same time.[1] |
| Permit steps and timeline | Every new ADU needs zoning, building and sewer use and drainage (SUDP) permits. A licensed contractor must pull the permits; homeowners cannot. The ADU needs its own address and a Certificate of Occupancy before anyone moves in. Mobile homes, RVs and tiny homes on wheels cannot be ADUs.[1] |
| Fees | Not verified. We did not find this on the official pages we checked. Ask the city before you design. |
Also worth knowing: Only one ADU is allowed per primary dwelling unit. Short-term rentals of ADUs need separate city licenses.[1]
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Sources
Every fact above links to an official city or state page. Rules change; check the source before you build.
- [1] City and County of Denver: Permitting an Accessory Dwelling Unit (ADU) checked Oct 2026
- [2] Denver CPD: Constructing Accessory Dwelling Units overview (updated Jun 13 2023) checked Oct 2026
- [3] Denver Maps: Accessory Dwelling Units checked Oct 2026