ADU Regulations in Colorado: The Complete Guide

Adding an Accessory Dwelling Unit (ADU) to your property in Colorado can offer flexible, practical housing options. Whether you’re hoping to create rental income, build a private living space for a family member, or provide an affordable home for a recent graduate, ADUs make it possible, often without altering your main residence.

However, figuring out what’s allowed can be confusing. Every city and county has its own rules on square footage, setbacks, placement, and permits, and in Colorado, those rules are in transition.

In 2024, Colorado passed House Bill 24-1152, which requires many municipalities to allow ADUs starting June 30, 2025. But the law doesn’t apply everywhere. It only affects what the state calls “subject jurisdictions.” These include:

• Cities or towns with 1,000+ residents located within a Metropolitan Planning Organization (MPO)
  
• Unincorporated areas of counties that fall within an MPO and lie in a Census Designated Place (CDP) with 40,000+ residents
  

While the new law will expand access to ADUs in many urban areas (including parts of the Denver metro, Colorado Springs, and the Northern Front Range), communities not covered by the bill still set their own ADU policies.

To simplify your search, we’ve gathered the most up-to-date ADU information for all 64 Colorado counties, along with contact details for each local planning department. We’ve also included a few cities where ADU rules differ from their surrounding county.

Are you curious to know if your property qualifies for an ADU, and what are your local requirements? Keep reading to find out. We’ll help you get the answers you need.

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Are ADUs Allowed in Colorado?

Yes, there are areas in Colorado who allow accessory dwelling units (ADUs). However, regulations and requirements for ADUs differ by location, so it’s important to consult your local municipality to understand how an ADU is defined in your area and whether they can be used as a dwelling unit.

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ADUs That Are Allowed in Colorado

At Zook Cabins, we offer a range of ADUs that are ideal for properties in Colrado. Our models start at a compact 597 square feet and go up to a spacious 848 square feet. Explore the designs below, we’re here to help you find the perfect fit for your property.

The A-Frame ADU

571- 848 sq.ft.

1 – 2 Bedroom(s)

1 Bathroom(s)

The Grove ADU

795 sq.ft.

1-2 Bedroom(s)

1-2 Bathroom(s)

The Sonoma ADU

672 sq.ft.

1 Bedroom(s)

1 Bathroom(s)

Can Log Cabins Be Used As An ADU?

Yes, log cabins could be used as ADUs, if they meet your local zoning and size requirements.

In most areas, an ADU must be smaller than the primary home and stay within a specific square footage limit set by your city or county. With that in mind, many of our log cabin models are already designed to fall within those common guidelines.

If a rustic look isn’t quite your style, we also offer a full line of modern-style cabins that may be a better fit for your needs, both in design and in compliance.

The Settler

660 – 1,700 sq.ft.

2 – 4 Bedroom(s)

1 – 2 Bathroom(s)

The Pioneer

650 – 1,700 sq.ft.

2 – 3 Bedroom(s)

1 – 2 Bathroom(s)

The Chalet

780 – 1700 sq.ft.

1 – 3 Bedroom(s)

1 – 2 Bathroom(s)

Can Modern Cabins Be Used As ADUs?

Yes, Modern Cabins as long as they meet the applicable size and placement requirements.

In Colorado, ADUs are typically between 600 and 1,200 square feet, though some jurisdictions may allow or require sizes that fall outside this range. We think this makes the Rio Grande and Two Pines Cabins perfect choices as they’re in line with these size requirements. Before you get started on building your ADU always confirm local regulations with your permitting authority to ensure they comply.

Below are some of our modern cabins designed within the 800–1,200 square foot range.

The Rio Grande

728 sq.ft.

1-2 Bedroom(s)

1 Bathroom(s)

The Two Pines

936 sq.ft.

2 Bedroom(s)

2 Bathroom(s)

The Woodland

738 – 1440 sq.ft.

2 – 3 Bedroom(s)

1 – 2 Bathroom(s)

Size & Placement Requirements for ADUs in Colorado

In many ways, an ADU functions just like a standard home. What makes it unique is that it shares a lot location with an existing primary residence and must meet certain size limitations. Below, we’ll explore these key differences in more detail.

What is the Minimum Size for an Accessory Dwelling Unit?

In some cases, Colorado has a minimum ADU size of 300 square feet.

However, the minimum size for an accessory dwelling unit in Colorado depends on your local jurisdiction. In some areas, the minimum square footage is calculated as a percentage of the primary residence. 

For instance, some areas may limit an ADU to no more than 25% of the main home’s total square footage. Since these regulations vary by location, it’s important to consult your local planning or zoning department to understand the size limits that apply to your property.

If your local rules limit ADUs to 400 square feet or less, our standard ADU models may not be a viable option. However, if park model homes are permitted as ADUs in your area, they can serve as a great alternative.

What are Park Models?

Can My ADU be Bigger Than My House?

No, an ADU cannot exceed the size of the primary structure on your property. In many jurisdictions, ADUs are also subject to a maximum square footage limit, which is often determined as a percentage of the main home’s total size.

How Close to My House Can I Build An ADU?

In most cases, Colorado law requires that ADUs be set back at least 5 feet from side and rear property lines. This minimum is established by House Bill 24-1152, which applies to many cities and counties across the state. However, the required distance between the ADU and the primary home, or any stricter setbacks, may still vary depending on your local zoning rules.

Be sure to contact your local planning, zoning, or building department to confirm what setback rules apply to your property.

Do You Need A Permit For An ADU in Colorado?

Yes, you will likely need building and zoning permits to add an ADU to your Colorado property.

Some areas may also require zoning approval, utility checks, or inspections. Even if state law says your city or county must allow ADUs, you still have to follow your local permit process. Rules vary by location, so check with your local building or planning department before getting started.

Are There Any Incentives or Grants for ADUs in Colorado?

Yes. According to Colorado’s Department of Local Affairs, the ADU Fee Reduction and Encouragement grant program to “provide grants to accessory dwelling unit supportive jurisdictions for activities that promote the construction of accessory dwelling units.” 

The Colorado Department of Local Affairs (DOLA) plans to launch the ADU grant program soon after subject jurisdictions can begin certification on June 30, 2025. Additional funding for ADU financing will be available through the Colorado Housing and Finance Authority (CHFA).

What Features are Included in An ADU from Zook Cabins?

Our ADUs come in a variety of contemporary designs and floor plans, so you can choose the layout that works best for your lifestyle. Every unit includes a fully finished interior with a kitchen, bedroom, and bathroom. Some interior features, like countertops, tile, and cabinet colors, can be personalized to match your preferences. For details on customization and to explore available models, visit our ADU page or speak with your sales representative.

Are Zook Cabin’s ADUs Built to Code?

Yes, all of our ADU models are designed to meet or exceed local requirements for size and room layout. They’re constructed similarly to modular homes and are intended to be placed on a permanent foundation.

If you’re unsure which type of foundation is right for your property, our team is here to help you find the best option.

Can an ADU Have Multiple Bedrooms and Bathrooms?

Yes, many ADUs are available with multiple bedrooms and bathrooms. Models like the Grove, Luna, and A-frame offer flexible layouts with one or two of each. Keep in mind, though, that the number of rooms you can include will depend on local zoning rules and size limits in your area.

Are ADUs A Good Investment?

Yes! Many people use ADUs as rental units to generate extra income. Though, we strongly suggest checking with your local guidelines to see whether this is permitted.  In some locations, financing programs are available to help with construction costs, and ADUs may even add resale value down the road. Check with your local regulations to see if any financial incentives apply in your area, they could make your ADU an even smarter investment. 

What Are the Requirements for ADUs in Each County in Colorado?

While Colorado House Bill 24‑1152 requires certain municipalities within urban areas to allow accessory dwelling units (ADUs), local governments not covered by the law can still adopt their own ADU policies. Counties and towns outside the state mandate retain the flexibility to implement zoning reforms tailored to local needs.

For example, Garfield County, which is not subject to HB24‑1152, permits ADUs in several residential and agricultural zones through its land use code. This demonstrates how non-mandated jurisdictions can voluntarily support housing diversity and affordability by legalizing ADUs on their own terms.

To make it easier to identify whether your county is covered by the law, we’ve organized them into two tables below, one for Subject Municipalities, one for those that are not subject to HB24‑1152, and one for those that have unclear regulations. You can skip the county list below if you already know your local jurisdiction.

If you live in an unincorporated area, or if your city or town does not have specific ADU requirements, refer to the officials listed below for guidance at the county level.

Subject Municipalities

*2023 population information from the Colorado Department of Local Affairs (State Demography Office)

Non-Subject Municipalities

*2023 population information from the Colorado Department of Local Affairs (State Demography Office

Does Adams County Allow ADUs?

Yes. Accessory dwelling units (ADUs) are permitted in Adams County, Colorado. According to county regulations, ADUs must meet the requirements for accessory structures, which include a minimum 5-foot setback from side and rear property lines. For the most accurate and current information, contact the Adams County Government Center.

Does Arapahoe County Allow ADUs?

Yes. Accessory dwelling units (ADUs) are allowed in unincorporated Arapahoe County under the county’s ADU regulations. Setback and dimensional standards depend on your zoning district, but typical accessory structure setbacks apply. For the most accurate and current regulations, contact the Arapahoe Building Division.

Does Boulder County Allow ADUs?

Yes. In Boulder, ADUs are permitted on residentially zoned lots, subject to city code. A detached ADU can occupy up to half the floor area of the main home (maximum 1,000 sq ft, or 750 sq ft if the house is under 1,500 sq ft), with larger allowances for designated affordable or historic units. Setbacks for accessory structures follow the Boulder Revised Code, with specifics outlined in Sections 9‑7‑1 through 9‑7‑4. For full details on size limits, design requirements, and permitting, contact Boulder Planning & Development Services.

Does Broomfield County Allow ADUs?

Yes. Broomfield permits ADUs in any zone where single-family homes are allowed, with regulations updated to align with state law. Setback requirements depend on your zone, following the standard accessory structure guidelines. For the most up-to-date rules, reach out to the Broomfield Planning Department.

Does Denver County Allow ADUs?

Yes. Denver authorizes ADUs through its Community Planning & Development Office and has guidance on how to apply for a permit. Under current zoning rules, one-story ADUs require a minimum 5-foot setback from property lines (rear). For the most accurate and current guidance, contact the Denver County Community Planning and Development Office.

Does Douglas County Allow ADUs?

Yes. Douglas County treats ADUs as residential additions and permits them through its Building Division, which oversees building and site plans for such structures. While zoning code does not list ADU setbacks explicitly, accessory structures in Estate Residential zones typically require 15-foot side setbacks and 25-foot rear setbacks. For the latest local codes, contact the Douglas County Building Division.

Does El Paso County Allow ADUs?

Yes. In unincorporated El Paso County, ADUs (referred to as “accessory living quarters”) are permitted and require only a building permit via the Pikes Peak Regional Building Department. Zoning rules limit ADU size to 1,500 square feet, and while utility-connection and location requirements apply, specific setback standards align with standard accessory structure rules, look to the county’s Land Development Code for exact zoning setback distances, which vary by district. For the latest regulations, contact the Pikes Peak Regional Building Department.

Does Grand County Allow ADUs?

Yes. Accessory dwelling units (ADUs) are allowed in Grand County, Colorado. According to the county’s guidelines, ADUs must be no greater than 50% of the square footage of the primary dwelling unit, or 1,500 square feet, whichever is less. For more information, contact the Grand County Planning and Zoning Department

Does Jefferson County Allow ADUs?

Yes. Jefferson County permits accessory dwelling units. The county allows a maximum ADU size of 600 square feet or 40% of the main home’s floor area, whichever is less. For more information, contact Jefferson County Building Safety.

Does Larimer County Allow ADUs?

Yes. Accessory dwelling units (ADUs) are allowed in unincorporated Larimer County. The county permits one ADU per residential lot, with a maximum size of 900 square feet, depending on lot size. While some parts of Larimer County, including the cities of Fort Collins and Loveland, are subject to Colorado House Bill 24‑1152 due to their location within a Metropolitan Planning Organization (MPO), unincorporated areas of the county are not automatically included and retain local control over ADU policy. For more details and current permit requirements, contact the Larimer County Building Department.

Does Mesa County Allow ADUs?

Yes. ADUs are allowed on single-family properties greater than 6,500 square feet in Mesa County. Specific size and setback requirements were not specified in the available data. For more information, contact the Mesa County Building Department.

Does Pueblo County Allow ADUs?

Likely. Pueblo County appears to allow ADUs, although requirements are less clearly defined in the current documentation. To confirm ADU eligibility and details for your property, contact the Pueblo County Planning and Development Department.

Does Teller County Allow ADUs?

Yes. ADUs are allowed in Teller County. However, specific minimum and maximum size details are not listed in the current county summary. For accurate and up-to-date requirements, contact the Teller County Building Division.

Does Alamosa County Allow ADUs?

Yes. ADUs are permitted in Alamosa County. The county specifies a minimum ADU size of 300 square feet and a maximum of 600 square feet. For more information, contact the Alamosa County Building Department.

Does Archuleta County Allow ADUs?

Yes. ADUs are allowed in Archuleta County. The minimum size is 400 square feet. For full details and local regulations, contact the Archuleta Building Department.

Does Baca County Allow ADUs?

Baca County does not have a dedicated building department. Building regulations, including those related to ADUs, may fall under the state’s Department of Housing oversight. For more information, visit the Colorado Department of Housing or contact the Baca County Office.

Does Bent County Allow ADUs?

Bent County’s ADU policy is not clearly defined. For clarification and current regulations, contact the Bent County Land Use Office.

Does Chaffee County Allow ADUs?

Yes. ADUs are allowed in Chaffee County. The maximum size is either 1,000 square feet or the floor area of the primary structure, whichever is smaller. For zoning confirmation and additional requirements, contact the Chaffee County Planning and Zoning Department.

Does Cheyenne County Allow ADUs?

Cheyenne County does not clearly define its ADU policy. To verify if ADUs are allowed on your property, contact the Cheyenne County Planning and Zoning Department.

Does Clear Creek County Allow ADUs?

Yes. ADUs are allowed in Clear Creek County. The maximum size is 1,500 square feet or 50% of the main home’s size, whichever is less. For setback information and other design requirements, contact Clear Creek County Planning and Building Services.

Does Conejos County Allow ADUs?

ADUs are not clearly addressed in Conejos County’s publicly available zoning information. For clarification and current guidelines, contact the Conejos Land Use Department.

Does Costilla County Allow ADUs?

Yes. ADUs are permitted in Costilla County. The minimum size is 600 square feet. The maximum is either 800 square feet or 50% of the primary dwelling’s size, whichever is less. For more information, contact the Costilla County Planning and Zoning Department.

Does Eagle County Allow ADUs?

Yes. Eagle County permits ADUs in various zoning districts, including those designated for affordable housing. The maximum size for a detached ADU is typically 850 square feet. All ADUs must comply with applicable zoning and land use codes. For full details, contact the Eagle County Planning Department.

Does Elbert County Allow ADUs?

Yes. ADUs are allowed in Elbert County. Specific requirements such as size and placement may vary depending on the zoning classification of the property. For accurate, up-to-date information, contact the Elbert County Building Department.

Does Fremont County Allow ADUs?

Yes. Fremont County permits ADUs. Specific size and design criteria may vary based on zoning district. For confirmation and permitting steps, contact the Fremont County Building Department.

Does Garfield County Allow ADUs?

Yes. Garfield County allows ADUs in certain residential and agricultural zones. ADUs must comply with the Unified Land Use Resolution and undergo review by the Community Development Department. For more details, contact Garfield County Community Development.

Does Gilpin County Allow ADUs?

Yes. Gilpin County permits ADUs, though size and placement requirements vary by zoning district. Property owners should review zoning standards carefully before proceeding. For more information, contact the Gilpin County Planning Department.

Does Grand County Allow ADUs?

Yes. ADUs are allowed in Grand County. The unit must not exceed 1,500 square feet or 50% of the main home’s square footage, whichever is less. For more information, contact the Grand County Planning and Zoning Department.

Does Gunnison County Allow ADUs?

Yes. ADUs are permitted in Gunnison County in several zoning districts. Requirements for size, location, and design vary by area. For zoning verification and construction guidelines, contact the Gunnison County Building Office.

Does Hinsdale County Allow ADUs?

Yes. Hinsdale County permits ADUs, but specific size and zoning criteria may vary. Property owners are encouraged to consult local regulations before planning an ADU. For current guidance, contact the Hinsdale Building Department.

Does Huerfano County Allow ADUs?

Yes. ADUs are allowed in Huerfano County. While detailed standards are not specified in the summary, permitting is handled through the Huerfano County Building Authority. For more information, contact the Huerfano County Building Authority.

Does Jefferson County Allow ADUs?

Yes. Jefferson County permits ADUs. The maximum size allowed is 600 square feet or 40% of the main home’s square footage, whichever is less. For more details, contact Jefferson County Building Safety.

Does La Plata County Allow ADUs?

Yes. La Plata County permits ADUs in many zoning districts. While detailed size restrictions depend on the specific land use classification, most detached ADUs are limited to 1,200 square feet or less. For full requirements, contact the La Plata County Building Department.

Does Las Animas County Allow ADUs?

Yes. Las Animas County allows ADUs. Specific standards and permit requirements may vary by zone. For complete guidance, contact the Las Animas County Building Department.

Does Lincoln County Allow ADUs?

Yes. Accessory dwelling units (ADUs) are allowed in Lincoln County. The minimum size is 700 square feet, though the exact square footage may vary depending on the lot size. For zoning standards and permit requirements, contact the Lincoln County Land Use Department.

Does Montrose County Allow ADUs?

Yes. ADUs are permitted in Montrose County, provided the property is at least one acre. Specific size or setback standards were not detailed in publicly available county regulations. For the official rules that apply to your property, please contact the Montrose County Building Division.

Does Ouray County Allow ADUs?

Yes. Accessory dwelling units are permitted in Ouray County. They must comply with land use regulations and may be subject to design or placement requirements depending on the property’s zoning. For accurate details on what’s allowed and how to apply, contact the Ouray County Land Use, Planning and Building Department.

Does Saguache County Allow ADUs?

Yes. Saguache County permits ADUs. The size allowance is 600 square feet or up to 1,400 square feet, depending on the acreage of the property. For full details on what’s allowed, contact the Saguache County Land Use Department.

Does San Juan County Allow ADUs?

Yes. ADUs are allowed in San Juan County. The minimum size is 400 square feet, and the maximum is 700 square feet. For zoning and permitting information, contact the San Juan County Building Department.

Does San Miguel County Allow ADUs?

Yes. Accessory dwelling units are allowed in San Miguel County. Specific requirements, including location, size, and use, vary by zoning district and property type. For accurate and up-to-date guidance, contact the San Miguel County Building and Planning Department.

Does Summit County Allow ADUs?

Yes. Summit County allows ADUs, depending on the zoning district. The maximum size may be 550 sq. ft., 1,000 sq. ft., or 1,400 sq. ft., based on property type and location. For official guidance, contact the Summit County Building Inspection Department.

Does Weld County Allow ADUs?

Yes. ADUs are permitted in Weld County. Specific size and zoning requirements depend on property classification. For more information, contact the Weld County Building Department.

Counties with Unclear ADU Regulations In Colorado

The following counties are unclear as to whether or not they currently allow ADUs. Some counties may or may not allow ADUs under certain conditions, but this has not been clearly established through publicly available regulations. Because policies can change and some counties may allow ADUs under specific review processes or zoning circumstances, we recommend contacting your county officials directly to confirm whether ADUs are permitted on your property.

Find Your Accessory Dwelling Units Requirements in Colorado By Municipality

What Are the ADU Requirements in Adams County, CO?

Adams County allows accessory dwelling units (ADUs) in areas zoned for single-family homes. According to the county’s ADU Submittal Requirements and the 2023 Zoning & Land Development Code:

• Minimum Size: 300 sq. ft.
• Maximum Size: 1,200 sq. ft. (varies based on lot size)
• Setbacks: Standard accessory structure setbacks apply—typically a minimum 5-foot side and rear setback, although smaller variances may be approved.
• Allowed ADUs per Lot: 1
• Permits Required: Building permit plus zoning approvals; additional reviews may be needed for septic systems, wells, or fire protection (as outlined in county documents).

Additional requirements may apply, so be sure to confirm compliance with the Adams County Government Center for complete instructions and forms.

What Are the ADU Requirements in Archuleta County, CO?

Archuleta County allows accessory dwelling units (ADUs) in permitted areas. According to the county’s Residential Building Packet and land use codes:

• Min. Living Area: 400 square feet
• Max Living Area: Not specified in official documentation
• Allowed ADUs per lot: 1 per residential lot (standard under IRC)
• Other Notes: ADUs must comply with the 2015 International Residential Code (IRC) and all zoning and permitting standards in effect at the time of application. Additional approvals may be required depending on location.

For the most accurate and current requirements, contact the Archuleta Building Department.

What Are the ADU Requirements in Alamosa County, CO?

Alamosa County permits accessory dwelling units (ADUs) in residential zones. According to county guidelines:

• Allowed ADUs: Yes
• Minimum Size: Not specified
• Maximum Size: 600 sq. ft.
  Setbacks: Follow standard accessory structure setbacks as per county zoning regulations
• Permits Required: Building permit (and zoning approval if needed)

For the most accurate and current requirements, contact the: Alamosa County Building Department

What Are the ADU Requirements in Arapahoe County, CO?

Arapahoe County allows accessory dwelling units (ADUs) in certain residential zones. ADUs are regulated by the county’s Land Development Code and permitting process:

• Allowed ADUs: Yes
• Minimum Size: Not specified
• Maximum Size: 600–1,200 sq. ft. depending on lot size
• Setbacks: Determined by zoning district (see Table 4-1.1 of the LDC)
• Permits Required: Zoning and building permits are required

Additional requirements may apply, so be sure to confirm compliance with the Arapahoe Building Division

What Are the ADU Requirements in Boulder County, CO?

Boulder County permits accessory dwelling units (ADUs) in residential zones, subject to detailed land use regulations and design standards:

• Allowed ADUs: Yes
• Minimum Size: Not specified
• Maximum Size: 800 sq. ft. (detached); 1,000 sq. ft. or less for attached units, depending on primary structure size and zoning
• Setbacks: Typically a minimum of 5 feet from property lines for detached ADUs
  Permits Required: Land Use review and building permit required

Additional requirements may apply, so be sure to confirm compliance with the Boulder Planning & Development Services

What Are the ADU Requirements in Broomfield County, CO?

Broomfield allows one accessory dwelling unit (ADU) per single-family residential lot. According to the City and County ADU Guide:

• Allowed ADUs per Lot: 1
• Maximum Size: No more than 50% of the principal dwelling’s footprint or 800 sq. ft., whichever is smaller
• Setbacks: Must meet the applicable accessory structure setback requirements for your zoning district; detached ADUs require a minimum 5-foot setback from rear and side property lines (per IRC-based accessory standards)
• Occupancy & Design Rules: ADUs are limited to 2 occupants, must be owner-occupied at time of permit application, and must design-match the primary home with at least 50% similar exterior materials
• Parking & Utilities: One additional off-street parking space is required, and ADUs must connect to the principal dwelling’s water

Additional requirements may apply, so be sure to confirm compliance with the Broomfield Planning Department

What Are the ADU Requirements in Chaffee County, CO?

Chaffee County permits accessory dwelling units (ADUs) in unincorporated areas under its Land Use Code and development standards, effective January 1, 2025. While the code confirms ADUs are allowed, there are no specific minimum or maximum size limits mentioned in publicly available county documents. Setbacks and development requirements apply as standard for accessory structures, and a zoning permit is required prior to applying for a building permit. For current zoning and placement rules, contact the Chaffee County Planning and Zoning Department.

What Are the ADU Requirements in Costilla County, CO?

Costilla County permits accessory dwelling units (ADUs) in certain residential and agricultural zones. According to the county’s planning resources:

• Allowed ADUs per Lot: 1
• Minimum Size: 600 sq. ft.
• Maximum Size: 800 sq. ft. or 50% of the main dwelling, whichever is less
• Setbacks: Must comply with zoning-specific requirements for accessory structures
• Permits Required: ADUs must be reviewed and approved by the Planning and Zoning Department before construction

Additional requirements may apply, so be sure to confirm compliance with Costilla County Planning and Zoning Department.

What Are the ADU Requirements in Delta County, CO?

Delta County permits accessory dwelling units (ADUs), though specific size or setback standards are not explicitly defined in publicly available resources. ADUs are generally treated as accessory residential uses and must comply with applicable zoning and building regulations.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Subject to standard accessory structure setbacks based on zoning district
• Permits Required: Building and zoning permits are required

Additional requirements may apply, so be sure to confirm compliance with the Delta County Planning and Community Development Department.

What Are the ADU Requirements in Denver County, CO?

Denver permits accessory dwelling units (ADUs) in eligible residential zones. ADUs must comply with the Denver Zoning Code and additional design standards.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Varies by zone lot size; detached ADUs are typically limited to 864 sq. ft.
• Setbacks: One-story ADUs must be set back at least 5 feet from rear property lines; two-story units may require 12–20 feet
• Design & Use Notes: Must meet height, lot coverage, and design compatibility standards
• Permits Required: Zoning, building, and utility permits are required, along with a Certificate of Occupancy

Additional requirements may apply, so be sure to confirm compliance with the Denver County Community Planning and Development Office.

What Are the ADU Requirements in Douglas County, CO?

Douglas County allows accessory dwelling units (ADUs) in certain residential zones, subject to zoning and building regulations.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not explicitly specified in public documents; detached ADUs are generally limited to 900 sq. ft.
• Setbacks: Must meet accessory structure setback standards as outlined in the zoning code
  Permits Required: Building permit required; may also need site plan approval based on location and use

There may be additional requirements, so be sure to confirm compliance with the Douglas County Building Division.

What Are the ADU Requirements in Eagle County, CO?

Eagle County permits accessory dwelling units (ADUs) in multiple zoning districts, including areas focused on workforce and affordable housing.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Typically limited to 850 sq. ft. for detached ADUs
• Setbacks: Must comply with the dimensional standards of the zoning district in which the ADU is proposed
• Permits Required: Building and zoning permits required; some locations may require additional site plan review

Additional requirements may apply, so be sure to confirm compliance with the Eagle County Planning Department.

What Are the ADU Requirements in El Paso County, CO?

El Paso County allows accessory dwelling units (ADUs), referred to as “accessory living quarters,” in many residential zoning districts.

• Allowed ADUs per Lot: 1
• Maximum Size: 1,500 sq. ft.
• Setbacks: Must meet the dimensional standards of the zoning district, including a minimum 5-foot side and rear setback for accessory structures
• Permits Required: Building permit required via Pikes Peak Regional Building Department

Additional requirements may apply, so be sure to confirm compliance with the El Paso County Planning and Community Development Department.

What Are the ADU Requirements in Elbert County, CO?

Elbert County allows accessory dwelling units (ADUs) in certain zoning districts. While specific square footage limits are not listed in publicly available materials, ADUs must comply with local zoning and building codes.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Determined by zoning classification and accessory structure guidelines
• Permits Required: Building permit required

Additional requirements may apply, so be sure to confirm compliance with the Elbert County Building Department.

What Are the ADU Requirements in Fremont County, CO?

Fremont County permits accessory dwelling units (ADUs), subject to building and zoning requirements. While specific ADU size limits are not published in the county’s public materials, ADUs must follow local zoning standards for accessory structures.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Must meet zoning district requirements for accessory buildings
• Permits Required: Building permit required
  

Additional requirements may apply, so be sure to confirm compliance with the Fremont County Building Department.

What Are the ADU Requirements in Garfield County, CO?

Garfield County permits accessory dwelling units (ADUs) in several residential and agricultural zones. ADUs must follow the Unified Land Use Resolution and are subject to administrative review.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Must meet the dimensional standards of the underlying zoning district
• Permits Required: Building permit and land use review required

Additional requirements may apply, so be sure to confirm compliance with the Garfield County Community Development.

What Are the ADU Requirements in Gilpin County, CO?

Gilpin County allows accessory dwelling units (ADUs), subject to zoning approval and building permit requirements. While specific ADU size limits are not publicly detailed, all structures must meet applicable zoning and building standards.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
  Setbacks: Must comply with accessory structure setbacks in the relevant zoning district
• Permits Required: Building permit required; zoning compliance review may also be necessary

Additional requirements may apply, so be sure to confirm compliance with the Gilpin County Planning Department.

What Are the ADU Requirements in Grand County?

Grand County allows accessory dwelling units (ADUs) in several zoning districts. ADUs must be subordinate in size to the primary dwelling.

• Allowed ADUs per Lot: 1
• Maximum Size: 1,500 sq. ft. or 50% of the main home’s size, whichever is less
• Setbacks: Must meet the zoning district’s accessory structure standards
• Permits Required: Zoning and building permits are required

Additional requirements may apply, so be sure to confirm compliance with Grand County Planning and Zoning Department.

What Are the ADU Requirements in Gunnison County?

Gunnison County permits ADUs in multiple zoning districts. Regulations may vary depending on location and land use designations.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Must comply with applicable zoning standards
• Permits Required: Building permit required 

Additional requirements may apply, so be sure to confirm compliance with Gunnison County Building Office.

What Are the ADU Requirements in Hinsdale County?

Hinsdale County allows ADUs in designated zones. While size limits are not clearly defined, accessory structures must comply with zoning and building codes.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Based on underlying zoning standards
• Permits Required: Building permit required

Additional requirements may apply, so be sure to confirm compliance with Hinsdale Building Department.

What Are the ADU Requirements in Huerfano County?

Huerfano County permits ADUs, though specific development standards may vary by zoning district.

• Allowed ADUs per Lot: 1
• Minimum / Maximum Size: Not specified
• Setbacks: Must comply with accessory building setback requirements
• Permits Required: Building permit required 

Additional requirements may apply, so be sure to confirm compliance with Huerfano County Building Authority.

What Are the ADU Requirements in Jefferson County?

Jefferson County allows ADUs in some residential zoning districts.

• Allowed ADUs per Lot: 1
• Maximum Size: 600 sq. ft. or 40% of the main dwelling, whichever is less
• Setbacks: Must meet accessory use setback standards for the zoning district
• Permits Required: Building permit required

Additional requirements may apply, so be sure to confirm compliance with Jefferson County Building Safety.

What Are the ADU Requirements in La Plata County?

La Plata County permits ADUs in several residential zones.

• Allowed ADUs per Lot: 1
• Maximum Size: 1,200 sq. ft.
• Setbacks: Must follow zoning-specific standards
• Permits Required: Building permit required 

Additional requirements may apply, so be sure to confirm compliance with La Plata County Building Department.

What Are the ADU Requirements in Larimer County?

Larimer County permits ADUs in unincorporated areas.

• Allowed ADUs per Lot: 1
• Maximum Size: 900 sq. ft.
• Setbacks: Must comply with dimensional requirements based on zoning
• Permits Required: Building permit required

Additional requirements may apply, so be sure to confirm compliance with Larimer County Building Department.

What Are the ADU Requirements in Lincoln County?

Lincoln County allows ADUs with minimum and maximum size requirements determined by lot size.

• Allowed ADUs per Lot: 1
• Minimum Size: 700 sq. ft.
• Maximum Size: Not specified
• Setbacks: Must meet applicable zoning requirements
• Permits Required: Building permit required

Additional requirements may apply, so be sure to confirm compliance with Lincoln County Land Use Department.

Searching For An ADU Builder Serving Colorado?

Our ADU lineup spans from 471 to 800 square feet, making them a great fit for most Colorado zoning standards. Whether you’re drawn to the Grove, A-Frame, and Luna, each model features flexible layouts with multiple bedrooms and bathrooms to support comfortable, everyday living. With a clean, contemporary design and a more accessible price point than traditional homes, these units are also ideal for use as rental properties.

In addition, depending on your local zoning, our park models, log cabins, or modern cabins may also meet ADU size limits, offering even more ways to find the right fit for your space and needs.

Tiny Home & ADU Rules By State: How Do They Compare?

Depending on where you live, park model tiny homes may be approved for use as an ADU, but it’s not guaranteed. Regulations don’t just vary from state to state; they can differ significantly between cities and even neighboring towns within the same county.

To see if park model tiny homes are allowed in your area, take a look at the table below. It includes the latest information, not just for Colorado, but for every state we deliver to.

If you’re not quite sure what sets park model tiny homes apart from ADUs, don’t worry, we’ve put together a clear, straightforward guide that breaks down the key differences between the two. Check it out to get a better understanding of which option is right for your property.