Yes. Since December 16, 2024, Denver has allowed one accessory dwelling unit on residential lots citywide, so most Berkeley single-family lots can add a backyard ADU or garage apartment if the design meets the zone district’s size, height, setback and permit rules.
For years, the answer in Berkeley depended on the exact zone district on your lot. Many blocks did not allow an accessory dwelling unit, which meant a rezoning with two public hearings before design could start. That changed in late 2024.
Denver City Council passed the Citywide ADUs measure on November 18, 2024, and it took effect on December 16, 2024. It also brought the city in line with Colorado’s 2024 ADU law, which required large Front Range cities to allow ADUs wherever single-unit homes are allowed by June 30, 2025.
Jason Sirois, a Denver Realtor with FORM at Compass, works out of our office at 1900 W 32nd Ave in Northwest Denver and hears this question from Berkeley owners on blocks between Sheridan and Federal Boulevards. Below is what the rules allow today, what still limits a project, how the permit process works, and what an ADU means when you sell or buy.
Can I build an ADU in my Berkeley backyard?
In most cases, yes. According to the city’s Citywide ADUs page, the 2024 measure updated the zoning code, the zoning map and the older Former Chapter 59 districts so that ADUs are allowed in all residential areas. The city says that opened about 70% of Denver’s land to ADUs, up from 36% before.
An ADU is a smaller, self-contained home on the same lot as the main house, with its own kitchen, bathroom and sleeping area. It can be a detached backyard cottage, an apartment over a garage, an addition, or converted space inside the house such as a basement or attic. It is not a separate property and cannot be sold on its own.
A few points apply to every Berkeley lot:
- One ADU per zone lot in single-unit districts.
- The ADU must be smaller than the zoning allowance for the main house.
- All ADUs need zoning, building, and sewer use and drainage permits.
- A licensed contractor must build it, and a certificate of occupancy is required before anyone lives there.
How big can a detached ADU be in Berkeley?
Size and shape come from the zone district’s building form standards. Much of Northwest Denver is in the Urban (U-) neighborhood context, but the exact district matters, so confirm yours on the city’s zoning map before you design. The city’s Constructing ADUs guide summarizes the main limits:
| Standard | What the city’s summary says |
|---|---|
| Location on the lot | Detached ADUs go in the rear 35% of the lot |
| Floor area, zone lot 7,000 sq ft or less | Up to 864 sq ft |
| Floor area, zone lot over 7,000 sq ft | Up to 1,000 sq ft |
| Height, Urban neighborhood context | Two stories and 24 feet |
| Vehicle access | From the alley if one exists; no second driveway from the street |
| Number per lot | One ADU per zone lot in single-unit districts |
Source: City and County of Denver, Constructing Accessory Dwelling Units (updated June 13, 2023) and Permitting an ADU page. These are summaries; the Denver Zoning Code controls.
Setbacks, bulk plane and lot coverage also shape what fits. On a narrow lot, the bulk plane, an angled line that limits how tall a building can rise near the side property lines, often decides whether a second story works. A survey is required if construction comes within three feet of a property line.
Can I convert my garage into an ADU?
Sometimes. Denver offers a path to convert an existing detached structure even if it does not meet every current form standard, but the structure must meet building and fire code for living space, including foundation, energy, utility and fire separation requirements. The city’s guide warns that most residential garages built on concrete slabs cannot be legally converted to living space. Any addition to a converted structure has to meet the current standards.
Tiny homes on wheels, RVs and travel trailers cannot be used as ADUs. And because new living space needs a sewer use and drainage permit, an older sewer line sometimes has to be replaced as part of the project.
Do I have to live on the property, and can I rent the ADU?
The owner-occupancy rule is much narrower than it used to be. Before the 2024 change, an ADU in a single-unit district could not be used if the owner did not live on the property. Under the current rules, the owner must live in the main house when applying for permits, unless the house and ADU are built at the same time. The city says the ADU can stay in use even if the owner later moves.
That follows Colorado’s House Bill 24-1152. The Colorado Department of Local Affairs explains that covered cities cannot require owner occupancy except at permit application or for a short-term rental license. It also says cities generally cannot require a new parking space for an ADU, and homeowners associations in covered areas cannot ban ADUs, though they can set reasonable rules.
Long-term rental of an ADU is allowed under these rules. Short-term rentals run under Denver’s separate licensing program, so check those requirements before planning on nightly rental income.
How does an ADU project get permitted in Denver?
Denver issues ADU permits through its online e-permits system, and homeowners cannot apply for the permits themselves; a licensed contractor applies. The steps on the city’s ADU permits page look like this:
- Confirm the zone district and zone lot standards, such as lot width, depth and street frontage.
- Prepare plans with an architect or designer who knows Denver’s ADU form standards.
- Submit zoning, building, and sewer use and drainage permits together so they can be reviewed at the same time.
- Pull trade permits for electrical, plumbing, mechanical and roofing.
- Pass inspections and receive a certificate of occupancy.
A property in a historic district or a designated landmark also needs a certificate of appropriateness, which the city recommends getting first. Trees in the public right of way or in a setback may require a call to the Office of the City Forester.
What does an ADU mean when you buy or sell in Berkeley?
A permitted ADU is part of the property and transfers with it. When an ADU is on a listing, the questions that matter are about the structure and its paperwork:
- Is there a certificate of occupancy for the ADU, or was it built as a studio, office or garage?
- Does the ADU have its own sewer connection, and when was the main sewer line last scoped?
- Does it share utility meters with the main house?
- Was it permitted before or after the December 2024 change, and does that affect how it can be used?
An ADU that is not yet built is a design question, not a price. If you are also wondering how Denver’s separate Unlocking Housing Choices proposal could affect a Berkeley lot, see our post on what Unlocking Housing Choices means for Berkeley single-family lots. For neighborhood context and recent listings, visit our Berkeley community page.
If you are weighing an ADU, a sale or a purchase in Berkeley, Jason Sirois and the FORM Team at Compass Denver are glad to talk through a specific address.
Frequently Asked Questions
When did Denver start allowing ADUs citywide?
Denver City Council passed the Citywide ADUs measure on November 18, 2024, and it went into effect on December 16, 2024. It allows ADUs in all residential areas of the city.
How big can an ADU be on a typical Berkeley lot?
The city’s summary allows up to 864 square feet on zone lots of 7,000 square feet or less, and up to 1,000 square feet on larger zone lots. The ADU must also be smaller than the zoning allowance for the main house.
Can a Berkeley ADU be two stories?
In the Urban neighborhood context, a detached ADU can be up to two stories and 24 feet, subject to setbacks and bulk plane. Narrow lots can limit the second story.
Do I need to live on the property to build an ADU in Denver?
Yes, at the time you apply for permits, unless the main house and ADU are built together. The city says the ADU can stay in use if the owner later moves.
Can I rent out an ADU in Berkeley after I move out?
Under the current rules, the ADU can keep being used after the owner moves away, so long-term rental is allowed. Short-term rentals follow Denver’s separate licensing rules.
Does an ADU need its own parking space?
Colorado’s 2024 ADU law generally prevents covered cities from requiring a new parking space for an ADU. Vehicle access has to come from the alley if the lot has one.
This article is general information based on City and County of Denver and Colorado Department of Local Affairs materials available as of October 30, 2026. It is not legal, tax or financial advice. Zoning and permit rules change and vary by lot; confirm requirements for your address with Denver Community Planning and Development and a licensed design professional.
