How Big Can an ADU Be? Maximum Allowed Sizes by State

The size of an Accessory Dwelling Unit (ADU) depends largely on where you live. Across the U.S., ADU size limits vary widely from city to city and state to state, influenced by local zoning laws and housing policies. Some places allow ADUs up to 1,200 square feet or more, while others restrict them to under 800 square feet.

If you’re planning to build an ADU, it’s important to understand your area’s specific rules to make sure your project complies. This guide breaks down the typical ADU size limits and regulations across all 50 states, helping you find what’s allowed in your community.

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How Big Can an ADU Be in California?

California is one of the most progressive states when it comes to ADU regulations, having passed several laws in recent years to encourage ADU construction and ease housing shortages.

Maximum Size Allowed

• Statewide maximum size: Generally, detached ADUs can be up to 1,200 square feet, while attached ADUs are typically limited to 50% of the existing home’s size or up to 1,200 square feet, whichever is less.
• Junior ADUs (JADUs): These smaller units must be no larger than 500 square feet.
• For detached ADUs under 800 sq ft, no parking is required under state law, easing the development process.

Key California Laws

• SB 13 (2019): Limits ADUs to 1,200 sq ft, establishes ministerial approval without discretionary review, and prohibits minimum lot sizes.
• SB 1069 & AB 68 (2017): Removes owner-occupancy requirements, waives certain impact fees for ADUs under 750 sq ft, and limits utility connection fees.
• SB 9 (2021): Allows lot splits and duplex creation on single-family lots, indirectly affecting ADU development potential.

Local Variations

Cities can adopt their own rules but must comply with the state’s baseline. For example:

• Los Angeles: Allows detached ADUs up to 1,200 sq ft or more with additional approvals. No parking required for units under 800 sq ft.
• San Francisco: Limits detached ADUs to 1,200 sq ft but often have stricter height and setback rules.
• San Diego: Detached ADUs can be up to 1,200 sq ft, with some flexibility for larger units in specific zones.

Height and Other Restrictions

• Height limit is generally 16 feet for detached ADUs, though some jurisdictions allow taller if it doesn’t affect neighbors.
• Setbacks are usually 4 feet from property lines.
• Floor Area Ratio (FAR) limits apply, but ADUs are often exempt or allowed additional FAR in many cities.

How Big Can an ADU Be in Texas?

Texas does not have statewide ADU regulations, so size limits and rules vary significantly between cities and counties.

Overview of ADU Size Regulations in Texas

Since Texas leaves ADU regulation largely to local jurisdictions, it’s essential to check municipal codes for the exact limits. However, here are guidelines from major cities:

Austin

• Max ADU size: Detached ADUs can be up to 1,100 square feet or 50% of the main house’s size, whichever is smaller.
• Attached ADUs: Generally, up to 50% of the main dwelling’s floor area.
• Junior ADUs: Not officially defined as a separate category but smaller units are treated like ADUs.
• Parking: One off-street parking space is usually required unless close to transit.
• Height: Up to 25 feet or two stories.
• Setbacks: Usually 5 feet from side and rear property lines.

Austin’s ADU rules aim to increase density while preserving neighborhood character.

Houston

• Houston does not currently have specific ADU regulations but allows accessory structures.
• ADU size is generally controlled by lot coverage and building code limits.
• Detached living units are often permitted as guest houses or secondary dwellings under certain zoning.
• Max size will depend on zoning district and lot size, typically not exceeding 1,000 sq ft in residential areas.

Dallas

• Dallas requires permits for ADUs under certain zoning districts.
• Typical size limits are not specified at the city level but are subject to zoning and lot coverage rules.
• Detached ADUs up to 1,000 sq ft are common, but confirm locally.

Summary for Texas

City	Max ADU Size	Notes
Austin	Up to 1,100 sq ft	Detailed ADU ordinance with parking rules
Houston	Varies, approx 1,000 sq ft	No specific ADU code, uses accessory structure rules
Dallas	Approx 1,000 sq ft	Dependent on zoning district

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How Big Can an ADU Be in Florida?

Florida does not have a statewide ADU law, so regulations vary widely by city and county. Many municipalities have adopted ADU-friendly ordinances recently, but size limits depend on local zoning.

Typical ADU Size Limits in Florida Cities

Miami-Dade County

• Maximum ADU size: Generally up to 800 to 1,000 square feet depending on zoning district.
• Attached ADUs: Often limited to 50% of the main house size or a specific square footage cap.
• Detached ADUs: Usually capped at 800 sq ft but some zones allow up to 1,000 sq ft.
• Parking: Parking requirements may be waived for ADUs near transit corridors.
• Height Limits: Typically limited to 16 to 20 feet or one story.
• Setbacks: Usually 5 feet from side and rear property lines.

Orlando

• Max ADU size: Often capped at 800 square feet or 50% of the main dwelling.
• Parking: One off-street parking space generally required.
• Height: Usually one story or 16 feet maximum.
• Setbacks: 5 feet minimum on side and rear.

Tampa

• Tampa has been updating zoning to encourage ADUs, typically allowing up to 800 square feet.
• Parking waivers may apply in some areas.
• Height usually limited to one story or 16 feet.

Summary for Florida

City	Max ADU Size	Notes
Miami-Dade	800 – 1,000 sq ft	Parking waivers near transit
Orlando	800 sq ft	One parking space required
Tampa	800 sq ft	Encouraging ADU-friendly zoning

How Big Can an ADU Be in New York?

New York State does not have statewide ADU legislation, so rules vary widely by locality, especially between New York City and the rest of the state.

New York City (NYC)

• NYC has recently eased ADU regulations to increase affordable housing options.
• Maximum ADU size: Typically, ADUs are limited to 800 to 1,200 square feet depending on zoning and building type.
• JADUs: Not specifically recognized in NYC zoning.
• Parking: Often waived in many zones to encourage development.
• Height: Usually limited to the height of the primary building or zoning district height limits.
• Setbacks: Vary by zoning district.

Key programs:

• The NYC Department of Housing Preservation and Development (HPD) offers resources and incentives for ADU development.
• New zoning text amendments (Zoning for Quality and Affordability — ZQA) have made ADUs more feasible.

Rest of New York State

• Most upstate municipalities regulate ADUs through local zoning ordinances.
• Typical ADU size limits: 800 to 1,000 sq ft.
• Parking and setback rules vary.
• Some areas do not permit ADUs at all.

Nassau County (Long Island)

• Nassau County allows ADUs with limits typically around 1,000 square feet.
• Owner-occupancy may be required.
• Parking usually required but may have exemptions.

Summary for New York

Location	Max ADU Size	Notes
NYC	800 – 1,200 sq ft	New zoning eases ADU rules
Nassau County	~1,000 sq ft	Owner-occupancy rules apply
Upstate NY	800 – 1,000 sq ft	Varies widely by local code

How Big Can an ADU Be in North Carolina?

North Carolina does not have statewide ADU legislation, so size limits and regulations vary by city and county. Many municipalities are in the early stages of adopting ADU-friendly ordinances.

Typical ADU Size Limits in North Carolina Cities

Charlotte

• Maximum ADU size: Detached ADUs are typically limited to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling’s size.
• Parking: One off-street parking space generally required unless close to transit.
• Height: Usually limited to one or two stories, often capped at 25 feet.
• Setbacks: Vary by zoning but typically 5 feet from side and rear property lines.

Charlotte has updated its zoning code to encourage ADU development as a strategy to increase affordable housing options.

Raleigh

• Raleigh permits ADUs in many residential zoning districts.
• Max size: Usually up to 1,000 square feet or 50% of the primary dwelling.
• Parking requirements can be waived in certain cases.
• Height limited to two stories or 25 feet.
• Setbacks generally 5 feet.

Summary for North Carolina

City	Max ADU Size	Notes
Charlotte	800 – 1,000 sq ft	Updated zoning encourages ADUs
Raleigh	Up to 1,000 sq ft	Parking waivers possible

How Big Can an ADU Be in Ohio?

Ohio does not have statewide ADU regulations, so size limits and other rules depend heavily on local city and county ordinances.

Typical ADU Size Limits in Ohio Cities

Columbus

• Maximum ADU size: Detached ADUs are generally limited to 800 to 1,200 square feet, depending on zoning district.
• Attached ADUs: Often capped at 50% of the primary dwelling size.
• Parking: One off-street parking space is typically required.
• Height: Usually limited to one or two stories, with height caps around 25 feet.
• Setbacks: Usually 5 feet from side and rear lot lines.

Columbus has made efforts to encourage ADU development as part of its housing strategy.

Cleveland

• ADUs are allowed in certain residential zones.
• Max size: Typically capped around 1,000 square feet.
• Parking and setback requirements vary by neighborhood.
• Height limits usually in line with zoning code.

Cincinnati

• ADUs permitted in some zoning districts.
• Typical maximum size between 800 and 1,000 sq ft.
• Parking usually required.
• Height and setback rules apply as per local zoning.

Summary for Ohio

City	Max ADU Size	Notes
Columbus	800 – 1,200 sq ft	Zoning dependent; parking usually required
Cleveland	~1,000 sq ft	Varies by neighborhood
Cincinnati	800 – 1,000 sq ft	Subject to local zoning

How Big Can an ADU Be in Oklahoma?

Oklahoma does not have statewide ADU legislation, and regulations vary significantly by city and county, with many areas still developing ADU-friendly policies.

Typical ADU Size Limits in Oklahoma Cities

Oklahoma City

• Maximum ADU size: Detached ADUs are generally limited to 800 to 1,200 square feet depending on zoning district.
• Attached ADUs: Usually capped at 50% of the primary dwelling size.
• Parking: One off-street parking space is typically required.
• Height: Height limits generally range between 16 to 25 feet.
• Setbacks: Usually require 5 feet from property lines.

Oklahoma City has been exploring ways to encourage accessory dwelling units to increase affordable housing options.

Tulsa

• Tulsa allows ADUs in certain residential zones.
• Max size: Typically capped at 1,000 square feet.
• Parking and setback requirements vary by neighborhood.
• Height usually limited to 16 to 25 feet.

Summary for Oklahoma

City	Max ADU Size	Notes
Oklahoma City	800 – 1,200 sq ft	Zoning-dependent with parking rules
Tulsa	Up to 1,000 sq ft	Varies by zone

How Big Can an ADU Be in Oregon?

Oregon has been a leader in ADU-friendly laws, with statewide regulations encouraging ADU construction to address housing shortages.

Statewide Maximum Size Limits

• Detached ADUs are generally allowed up to 800 square feet.
• Attached ADUs can be larger, often up to 1,000 square feet or 50% of the primary dwelling size.
• Junior ADUs (JADUs) are allowed up to 500 square feet.

Key Oregon Laws

• House Bill 2001 (2019): Requires cities with populations over 10,000 to allow ADUs and duplexes in single-family zones.
• Cities cannot impose owner-occupancy requirements or parking minimums for ADUs in many cases.
• Impact fees and certain regulations are limited to encourage ADU development.

Local Variations

• Portland: Detached ADUs allowed up to 800 square feet with height limits of 16 feet. Attached ADUs and JADUs follow state guidelines.
• Eugene: Similar rules to Portland with 800 sq ft max for detached ADUs.
• Salem: ADUs allowed up to 800 sq ft with relaxed parking requirements.

Height and Setbacks

• Height is usually limited to 16 feet for detached ADUs.
• Setbacks are often minimal, commonly 3 to 5 feet from property lines.

Summary for Oregon

City	Max ADU Size	Notes
Portland	Up to 800 sq ft	State laws limit parking & fees
Eugene	Up to 800 sq ft	Similar to Portland
Salem	Up to 800 sq ft	Relaxed parking requirements

How Big Can an ADU Be in Pennsylvania?

Pennsylvania does not have statewide ADU regulations, so size limits and rules vary widely by municipality. Many cities are beginning to adopt ADU-friendly ordinances to address housing needs.

Typical ADU Size Limits in Pennsylvania Cities

Philadelphia

• Maximum ADU size: Detached ADUs typically allowed up to 800 to 1,000 square feet.
• Attached ADUs: Usually limited to 50% of the primary dwelling’s size.
• Parking: Often required but may be waived in some neighborhoods.
• Height: Usually limited to one or two stories, often capped at 25 feet.
• Setbacks: Usually 5 feet from property lines.

Philadelphia has been encouraging ADU construction through zoning code updates and pilot programs.

Pittsburgh

• ADUs are permitted in select residential zoning districts.
• Max size: Typically around 800 to 1,000 square feet.
• Parking and setback requirements vary.
• Height restrictions generally align with zoning.

Summary for Pennsylvania

City	Max ADU Size	Notes
Philadelphia	800 – 1,000 sq ft	Parking requirements vary
Pittsburgh	800 – 1,000 sq ft	Zoning-dependent

How Big Can an ADU Be in Rhode Island?

Rhode Island does not currently have statewide ADU legislation, and regulations vary by city and town. Several municipalities have started adopting ADU-friendly policies.

Typical ADU Size Limits in Rhode Island Cities

Providence

• Maximum ADU size: Detached ADUs typically allowed up to 800 to 1,000 square feet.
• Attached ADUs: Often caped at 50% of the primary residence.
• Parking: Usually required, but some exemptions exist for transit-accessible areas.
• Height: Usually limited to 1 or 2 stories, generally under 25 feet.
• Setbacks: Typically 5 feet or more from property lines.

Providence encourages ADU development as part of its affordable housing strategy.

Summary for Rhode Island

City	Max ADU Size	Notes
Providence	800 – 1,000 sq ft	Parking requirements vary

How Big Can an ADU Be in South Carolina?

South Carolina does not have statewide regulations governing ADU size, so limits and rules vary by municipality. Several cities have started adopting ADU ordinances to address housing needs.

Typical ADU Size Limits in South Carolina Cities

Charleston

• Maximum ADU size: Detached ADUs are generally limited to 800 to 1,000 square feet, depending on zoning.
• Attached ADUs: Typically capped at 50% of the primary dwelling size.
• Parking: Usually one off-street parking space is required, but waivers may apply.
• Height: Generally limited to 1 or 2 stories, with maximum heights around 25 feet.
• Setbacks: Minimum setbacks often 5 feet from side and rear property lines.

Charleston has been updating zoning regulations to encourage ADUs as part of its housing strategy.

Columbia

• ADUs are allowed in select zoning districts.
• Max size: Typically capped at 800 to 1,000 sq ft.
• Parking and setback requirements vary by area.
• Height restrictions generally consistent with local zoning codes.

Summary for South Carolina

City	Max ADU Size	Notes
Charleston	800 – 1,000 sq ft	Parking requirements vary
Columbia	800 – 1,000 sq ft	Zoning-dependent

How Big Can an ADU Be in South Dakota?

South Dakota does not have statewide ADU regulations, and most size limits and zoning rules are set at the local level. Many towns and cities have limited or no formal ADU policies yet.

Typical ADU Size Limits in South Dakota Cities

Sioux Falls

• Maximum ADU size: Detached ADUs are typically limited to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling’s size.
• Parking: One off-street parking space generally required.
• Height: Height limits vary but typically range from 16 to 25 feet.
• Setbacks: Usually a minimum of 5 feet from property lines.

Sioux Falls is gradually developing ADU-friendly ordinances to increase housing options.

Summary for South Dakota

City	Max ADU Size	Notes
Sioux Falls	800 – 1,000 sq ft	Parking and setbacks required

How Big Can an ADU Be in Tennessee?

Tennessee does not have statewide ADU regulations, so size limits and rules vary by municipality. Some cities have adopted ADU-friendly ordinances, but many rely on general accessory structure rules.

Typical ADU Size Limits in Tennessee Cities

Nashville

• Maximum ADU size: Detached ADUs can be up to 1,000 to 1,200 square feet, depending on zoning.
• Attached ADUs: Typically limited to 50% of the primary dwelling size.
• Parking: Usually one off-street parking space required unless near transit.
• Height: Height limits generally range from 16 to 25 feet.
• Setbacks: Typically 5 feet from property lines.

Nashville has been proactive in updating zoning codes to support ADU construction for affordable housing.

Memphis

• ADUs are allowed in certain residential zones.
• Max size: Generally capped at around 800 to 1,000 square feet.
• Parking and setbacks vary depending on neighborhood.
• Height limits typically align with zoning codes.

Summary for Tennessee

City	Max ADU Size	Notes
Nashville	1,000 – 1,200 sq ft	Updated zoning supports ADUs
Memphis	800 – 1,000 sq ft	Varies by neighborhood

How Big Can an ADU Be in Texas?

Texas does not have statewide ADU regulations, so size limits and rules vary widely by city and county. Local jurisdictions set their own standards for ADU size, parking, and setbacks.

Typical ADU Size Limits in Major Texas Cities

Austin

• Maximum ADU size: Detached ADUs can be up to 1,100 square feet or 50% of the main house’s size, whichever is smaller.
• Attached ADUs: Generally limited to 50% of the primary residence.
• Parking: One off-street parking space is usually required unless near public transit.
• Height: Height limits are typically up to 25 feet or two stories.
• Setbacks: Generally 5 feet from property lines.

Austin encourages ADU construction as part of its housing strategy to increase density and affordability.

Houston

• Houston does not have specific ADU regulations but allows accessory dwelling units under accessory building rules.
• Size limits are generally controlled by zoning and lot coverage restrictions.
• Detached living units typically range up to 1,000 square feet, depending on zoning district.

Dallas

• ADUs are permitted in select zoning districts.
• Typical maximum size ranges from 800 to 1,000 square feet.
• Parking and setback requirements vary by neighborhood.

Summary for Texas

City	Max ADU Size	Notes
Austin	Up to 1,100 sq ft	Detailed ADU ordinance with parking rules
Houston	Up to 1,000 sq ft	Regulated by accessory building codes
Dallas	800 – 1,000 sq ft	Subject to local zoning

How Big Can an ADU Be in Utah?

Utah does not have statewide ADU regulations; size limits and zoning rules are determined at the city or county level. Several cities have adopted ADU-friendly policies to address housing demands.

Typical ADU Size Limits in Utah Cities

Salt Lake City

• Maximum ADU size: Detached ADUs are typically limited to 800 to 1,200 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling’s size.
• Parking: One off-street parking space required, with some exemptions near transit corridors.
• Height: Generally limited to 16 to 25 feet.
• Setbacks: Usually 5 feet from property lines.

Salt Lake City encourages ADU construction as part of its affordable housing initiatives.

Provo

• Provo allows ADUs in several residential zones.
• Max size: Typically up to 1,000 square feet.
• Parking and setback requirements vary by neighborhood.
• Height restrictions typically consistent with local zoning.

Summary for Utah

City	Max ADU Size	Notes
Salt Lake City	800 – 1,200 sq ft	Parking requirements may vary
Provo	Up to 1,000 sq ft	Local zoning dependent

How Big Can an ADU Be in Vermont?

Vermont does not have statewide ADU regulations, so size limits and rules vary by town and municipality. Some towns have adopted ADU-friendly ordinances, while others regulate ADUs as accessory structures.

Typical ADU Size Limits in Vermont Towns

Burlington

• Maximum ADU size: Detached ADUs are typically limited to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling size.
• Parking: One off-street parking space generally required.
• Height: Height limits usually range from 16 to 25 feet.
• Setbacks: Typically 5 feet or more from property lines.

Burlington encourages ADU development to increase affordable housing availability.

Summary for Vermont

Town	Max ADU Size	Notes
Burlington	800 – 1,000 sq ft	Parking requirements apply

How Big Can an ADU Be in Virginia?

Virginia does not have statewide ADU regulations; size limits and requirements vary widely by locality. Many cities have adopted ADU-friendly ordinances to address housing needs.

Typical ADU Size Limits in Virginia Cities

Richmond

• Maximum ADU size: Detached ADUs typically allowed up to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling size.
• Parking: One off-street parking space generally required, with possible waivers near transit.
• Height: Usually limited to one or two stories.
• Setbacks: Typically 5 feet from property lines.

Richmond has updated its zoning code to encourage ADU development for affordable housing.

Arlington

• ADUs are permitted in many residential zones.
• Max size: Typically capped at 800 to 1,000 square feet.
• Parking waivers may apply.
• Height and setback requirements are based on zoning district.

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Summary for Virginia

City	Max ADU Size	Notes
Richmond	800 – 1,000 sq ft	Parking may be waived near transit
Arlington	800 – 1,000 sq ft	Parking waivers possible

How Big Can an ADU Be in Washington?

Washington State has taken progressive steps to encourage ADU development statewide, with regulations varying somewhat by city and county.

Statewide Guidelines

• Detached ADUs are typically allowed up to 1,000 square feet.
• Attached ADUs may be larger but are often capped at 50% of the primary residence size.
• Many cities have eliminated parking requirements for ADUs close to transit.
• Height limits generally range from 16 to 25 feet, with setbacks typically 4 to 5 feet.

Local City Examples

Seattle

• Maximum ADU size: Detached ADUs up to 1,000 square feet.
• Attached ADUs: Generally limited to 50% of the primary dwelling size.
• Parking is not required for ADUs built near frequent transit service.
• Height limit for detached ADUs is 16 feet.
• Setbacks of 4 feet are common.

Seattle’s policies aim to increase affordable housing supply by easing ADU construction.

Spokane

• ADUs allowed up to 800 to 1,000 square feet.
• Parking requirements may be waived near transit corridors.
• Height and setback requirements based on zoning.

Summary for Washington

City	Max ADU Size	Notes
Seattle	Up to 1,000 sq ft	Parking often waived near transit
Spokane	800 – 1,000 sq ft	Zoning-dependent

How Big Can an ADU Be in West Virginia?

West Virginia does not have statewide ADU regulations, and most size limits and zoning requirements are determined at the local level. Many municipalities have limited or no formal ADU policies yet.

Typical ADU Size Limits in West Virginia Cities

Charleston

• Maximum ADU size: Detached ADUs are typically limited to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the primary dwelling size.
• Parking: One off-street parking space generally required.
• Height: Height limits usually range between 16 and 25 feet.
• Setbacks: Usually 5 feet from property lines.

Charleston has been exploring ADU ordinances to increase housing options.

Morgantown

• ADUs allowed in select zoning districts.
• Max size: Generally capped at around 800 to 1,000 square feet.
• Parking and setback requirements vary.
• Height limits align with zoning codes.

Summary for West Virginia

City	Max ADU Size	Notes
Charleston	800 – 1,000 sq ft	Parking and setbacks required
Morgantown	800 – 1,000 sq ft	Local zoning dependent

How Big Can an ADU Be in Wisconsin?

Wisconsin does not have statewide ADU regulations; size limits and zoning rules vary by municipality. Many cities are starting to adopt ADU-friendly policies to help increase housing supply.

Typical ADU Size Limits in Wisconsin Cities

Milwaukee

• Maximum ADU size: Detached ADUs generally limited to 800 to 1,000 square feet.
• Attached ADUs: Usually capped at 50% of the main house’s size.
• Parking: One off-street parking space often required.
• Height: Typically limited to 16 to 25 feet.
• Setbacks: Generally 5 feet from property lines.

Milwaukee has recently updated zoning to encourage ADU development.

Madison

• ADUs are allowed in many residential zones.
• Max size: Often capped at around 1,000 square feet.
• Parking and setback rules vary.
• Height limits align with zoning codes.

Summary for Wisconsin

City	Max ADU Size	Notes
Milwaukee	800 – 1,000 sq ft	Parking usually required
Madison	Up to 1,000 sq ft	Zoning-dependent

How Big Can an ADU Be in Wyoming?

Wyoming does not have statewide ADU regulations, and local zoning ordinances set the standards for ADU size and other requirements. Many communities are just beginning to consider ADUs as part of housing strategies.

Typical ADU Size Limits in Wyoming Cities

Cheyenne

• Maximum ADU size: Detached ADUs generally limited to 800 to 1,000 square feet.
• Attached ADUs: Typically capped at 50% of the primary dwelling size.
• Parking: Usually one off-street parking space required.
• Height: Height limits vary, commonly 16 to 25 feet.
• Setbacks: Usually 5 feet from property lines.

Cheyenne is exploring ways to encourage ADUs to increase affordable housing availability.

Casper

• ADUs are allowed in select zoning districts.
• Max size: Typically capped at 800 to 1,000 square feet.
• Parking and setback requirements vary locally.
• Height restrictions align with zoning codes.

Summary for Wyoming

City	Max ADU Size	Notes
Cheyenne	800 – 1,000 sq ft	Parking and setbacks required
Casper	800 – 1,000 sq ft	Local zoning dependent

Conclusion

ADU size regulations vary greatly across the U.S. While some states have progressive, statewide ADU-friendly laws, most leave the details to local jurisdictions. Understanding your city or county’s rules is essential for planning your ADU project successfully.

Frequently Asked Questions

Can I build an ADU anywhere on my property?
ADUs must follow local zoning and setback rules. Detached ADUs usually require minimum distances from property lines to ensure privacy and safety.

Are there height limits for ADUs?
Yes, height limits generally range between 16 and 25 feet, depending on your local zoning regulations.

Is parking required for ADUs?
Parking requirements vary by location. Some cities mandate one off-street parking space, while others waive this if the property is near public transit.

How do I get a permit for an ADU?
To get a permit, you need to submit your building plans to the local planning or building department and comply with zoning and building codes. The process may involve reviews and inspections.