The rules that matter before you call a builder
| Rule | What Denver says |
|---|---|
| Where | Any zone district that allows a new single-unit dwelling; one ADU per primary dwelling unit |
| Owner occupancy | In single-unit districts the owner must live in the main house when applying, unless both are built at once; since the 2024 change the ADU may still be used if the owner moves later |
| Who builds | "ADUs must be built by a licensed contractor"; "Homeowners cannot apply for permits to build an ADU" |
| Size, height, setbacks | Set per zone district in the Denver Zoning Code |
| Not allowed as an ADU | Mobile homes, RVs, tiny homes on wheels, travel trailers |
| Driveway | No separate driveway unless the new access is from an alley |
| Address | The ADU gets its own address |
| Renting it short-term | Short-term rentals, ADUs included, need a City license |
| HOAs | The City does not review HOA rules; state law HB 24-1152 overrides HOA rules that prevent ADUs |
Sources: the Citywide ADUs project page and the City's ADU permit page.
The permit, step by step
- Zoning, building and sewer use (SUDP) together. The contractor applies in E-permits under "New Accessory Dwelling Unit" and uploads the documents with the first application so all three reviews run at once.
- Survey only if construction is within three feet of a property line (improvement survey when structures exist).
- Soils report. The City's checklist for new homes and additions requires a current geotechnical soils report for new conditioned accessory structures and wherever expansive soils are likely (DRC R401.4). Budget for it in a detached ADU quote.
- Trade permits for electrical, plumbing, mechanical and roofing go through Quick Permits; since 22 May 2025 new construction needs an issued Residential Construction Permit first.
- Other approvals as they apply: a certificate of appropriateness in a landmark district, the City Forester for right-of-way or protected trees, a demolition permit for a garage you are replacing, and Denver Water, where "a new license may be required" and extra fees may apply.
- Certificate of Occupancy before anyone lives in it.
What 262 Denver ADU permits show
| Measure | Denver ADU |
|---|---|
| Permits, October 2023 to September 2026 | 262 |
| Firms / active in the last year of data | 162 / 77 |
| Usual filed value | $137,144 |
| Middle half of builders' usual value (24 builders) | $102,992 to $175,000 |
| Builders with a single ADU permit | 122 (75.3%) |
| Busiest / quietest month | June (128) / February (68) |
ADU building in Denver is spread thin: 75.3% of the firms on these permits filed only one. Most contractors you talk to will have built one or two, so ask for the address of a finished ADU and look up its permit and Certificate of Occupancy yourself. A detached ADU usually sits next to a garage rebuild or addition in the same file; compare Denver addition cost and Denver garage cost. Filed values by firm are on Denver ADU cost.
Compare Denver ADU builders by permits →
Related
Licenses: Denver contractor license lookup. Finding a permit by address: Denver building permit search. ADU or addition: ADU vs addition. Statewide licensing: checking a contractor license in Colorado.
What this does not tell you
Denver's records do not give a reliable close date for ADU permits, so we show no completion rate or timeline for them. Filed values are construction estimates on the application, not the final cost, and leave out tap fees and design. Zone district standards decide what fits on a given lot; check them with the City before paying for plans.
How we know this
Rules are from Denver Community Planning and Development's Citywide ADUs page, the ADU permit page and the Permitting Checklist for New Homes and Additions, all read 23 October 2026. Permit counts are City and County of Denver residential permits classified as ADUs, October 2023 to September 2026; the firm range uses builders with three or more ADU permits.
Numbers come from City and County of Denver residential construction and demolition permits, data through October 16, 2026. Nobody paid to be on this page and nobody can.
Questions
- Are ADUs allowed everywhere in Denver?
In all residential areas. City Council passed the Citywide ADUs measure on 18 November 2024 and it took effect on 16 December 2024, allowing ADUs on 70% of Denver's land, up from 36%. ADUs are allowed in every zone district that allows a new single-unit dwelling.
- Do I have to live on the property to build an ADU in Denver?
In single-unit zone districts, the owner must live in the main house when applying for the ADU permits, unless the house and ADU are built at the same time. Since the 2024 change, the ADU can still be used if the owner later moves away.
- Can a homeowner pull an ADU permit in Denver?
No. Denver's ADU permit page says ADUs must be built by a licensed contractor and homeowners cannot apply for the permits to build one.
- How much does an ADU cost in Denver?
The usual Denver ADU permit was filed at $137,144 (262 permits, October 2023 to September 2026), and the middle half of builders with three or more ADU permits usually filed between $102,992 and $175,000. That is construction value, before design, tap fees and soils work.
- Can my HOA stop me from building an ADU in Denver?
The City says it does not regulate or review HOA rules and tells owners in metro districts or HOAs to check their bylaws. The state law the measure implements, House Bill 24-1152, overrides HOA rules that prevent ADUs, according to Denver Community Planning and Development.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Do I need a permit for an ADU? Yes; here is what 9 cities require, and how long it takes
- Bellingham ADU rules under the 2025 interim ordinance: two per lot, 1,000 sq ft, no owner occupancy, and what ADU permits show
- Can an unpermitted ADU be legalized? California's AB 2533 rule, and what it costs and takes
- Nashville DADU rules: where a backyard cottage is allowed, the 700/850 sq ft limits, and who can pull the permit
- Do I need a solar permit in Prince George's County? Building and electrical permits, the per-watt fee, SolarAPP+, and 9,331 permits
- Raleigh ADU rules: sizes, setbacks, the Not For Rent rule for owner-builders, and what ADU permits were filed at
For one city
- Citywide ADUs — Denver Community Planning and Development (accessed 2026-10-23)
- Permitting an Accessory Dwelling Unit (ADU) — City and County of Denver (accessed 2026-10-23)
- Permitting Checklist for New Homes and Additions — Denver CPD (accessed 2026-10-23)