Denver ADU rules
✓ Verified against code · August 19, 2026
Current rules under Denver Zoning Code §11.8.2 and Article 3/5 form standards, adopted by CB24-1302 (amended by CB25-0684, CB25-2163), in effect since December 16, 2024. Denver's citywide ADU ordinance (CB24-1302) ended parcel-by-parcel rezonings in December 2024, a follow-up repealed all vehicle-parking minimums citywide in August 2025, and a February 2026 amendment forced PUDs to allow ADUs. The city's own 2023 'Constructing an ADU' handout, still linked from its permits page, describes the pre-2024 regime — ignore it.
Common questions, answered from the code
Do I need a rezoning to build an ADU in Denver?
Not anymore. CB24-1302 made ADUs a use by right citywide wherever single-unit homes are allowed, effective December 16, 2024 — ending the parcel-by-parcel rezoning era. Guides describing the rezoning process, including the city's own older handout, predate the change.
CB24-1302; DZC §11.8.2.1 · Permalink
Do I need parking for a Denver ADU?
No. Denver repealed minimum vehicle parking citywide effective August 11, 2025 — for ADUs and everything else.
CB25-0684 · Permalink
How big can a Denver ADU be?
In single-unit districts the cap is a building footprint of 864 sq ft (lots up to 7,000 sq ft) or 1,000 sq ft (larger lots) — and because it's a footprint cap, a two-story ADU can roughly double the livable space within it. Urban-context height allows 2 stories / 24 ft.
DZC §11.8.2.1.B.2; §5.3.4.5 · Permalink
Do I have to live on the property?
Not on an ongoing basis. In single-unit districts, you must own both units and — when adding an ADU to an existing house — occupy the primary home at the time you apply, which is exactly the carve-out Colorado's ADU statute permits. After that, both units can be rentals (long-term; STR rules differ).
DZC §11.8.2.2; C.R.S. 29-35-403(2)(b) · Permalink
The rules at a glance
| ADUs allowed per lot | One ADU per primary dwelling unit; in single-unit (SU) districts, one per zone lot, attached or detached. ADUs accessory to two-unit or multi-unit primaries must be detached.DZC §11.8.2.1.A.1–.2Previously: ADUs required a parcel-by-parcel rezoning through city council — changed by CB24-1302, effective Dec 16, 2024 |
| Maximum size | SU districts: building footprint capped at 864 sq ft on lots of 7,000 sq ft or less, 1,000 sq ft on larger lots — footprint, not floor area, so a two-story unit can roughly double the space. Non-SU attached ADUs: up to the greater of 75% of the primary's floor area or 864 sq ft.DZC §11.8.2.1.B.2; §5.3.4.5 |
| Detached ADU height | Urban contexts: 2 stories / 24 ft with a side-lot-line bulk plane (12 ft on lots ≤40 ft wide, then 45°). Suburban: 1 story/17 ft, or 2 stories/24 ft with a 20-ft rear setback. The ADU must sit in the rear 35% (urban) or 50% (suburban) of the lot.DZC §5.3.4.5 form tables |
| Detached ADU setbacks | Urban: side 3 ft (lots ≤40 ft) or 5 ft; rear 5 ft without an alley — with an alley, 5 ft if garage doors face it, 0 ft if they don't. Suburban: side 3/5/7.5 ft by lot width; rear 10 ft (one story) or 20 ft (two). Vehicle access must come from the alley where one exists.DZC §5.3.4.5; §11.8.2.1.C.1 |
| Off-street parking | None. Denver repealed all minimum vehicle parking requirements citywide effective August 11, 2025.CB25-0684; DZC Div. 10.4Previously: Minimum vehicle parking applied per zone — changed by CB25-0684, effective Aug 11, 2025 |
| Owner-occupancy | No ongoing occupancy requirement. In SU districts, both units must stay under common ownership, and an owner must occupy the primary home at the time of permit application when adding an ADU to an existing house (waived for simultaneous new construction and DHA properties) — the exact carve-out state law allows.DZC §11.8.2.2.A–.B; C.R.S. 29-35-403(2)(b) |
| Lot coverage / floor area | A detached ADU counts toward the primary form table's maximum building coverage (Urban House: 60/45/40% by lot width). No ADU-specific bonus.DZC §5.3.4.5; Art. 5 form tables |
| Permit path & timeline | Use by right citywide where single-unit dwellings are allowed — no rezoning since December 2024. Zoning permit + building permit + sewer use & drainage permit; a licensed contractor is required (homeowners can't self-permit). No fixed timeline — the city publishes only a live average-review-times dashboard.CB24-1302; Denver CPD ADU permits page |
Worth knowing
- Carriage-lot ADUs are allowed without any primary dwelling — rare anywhere.
- The WDSF+ pilot (Denver Housing Authority / West Denver Renaissance Collaborative) offers design and finance support for income-restricted-rent ADUs, expanded citywide.
- Short-term renting an ADU requires the host to live in the primary structure (Denver's STR primary-residence rule).
- Denver is not on the state's certified ADU-supportive-jurisdiction list, so it doesn't participate in the HB24-1152 fee-reduction grant program.
- A rooftop deck up to 100 sq ft is allowed on alley-adjacent ADUs; no tiny-homes-on-wheels or RVs.
On our watchlist
The at-application owner-occupancy rule for existing-house ADUs draws ongoing criticism and is a likely future amendment target; nothing is filed after CB25-2163 (Feb 2026).
Check your parcel
The rules above are citywide — what you can build depends on your lot’s zone, size, and setbacks. Look yours up on the official viewers:
Primary sources
Other Colorado cities
Arvada · Aurora · Boulder · Colorado Springs · Fort Collins · Greeley · Lakewood · Longmont · Pueblo · Thornton · Westminster
Not legal advice. Every fact above cites the code section it comes from — check the cite, or ask your city’s planning department to confirm your specific lot. Spotted an error or a new ordinance? See about to reach us; corrections are logged in the changelog.