Accessory Structures
ADU rules, shed permits, and garage conversion regulations.
Accessory Structures rules vary widely between U.S. cities and counties. What is permitted in one jurisdiction may carry fines or require permits in another. This hub brings together everything on CityRuleLookup related to accessory structures: subtopics, city-specific data, expert guides, and rankings.
Browse Accessory Structures Topics
ADU Rules
Rules for building accessory dwelling units (granny flats, in-law suites) including size limits, parking requirements, and owner-occupancy rules.
655 locationsADU Permits
How to apply for an ADU building permit: application steps, plan-check requirements, review timelines, ministerial vs discretionary review, and which department to file with.
9 locationsADU Impact Fees
Impact fees, school fees, utility hookup charges, and waivers for ADUs. Many jurisdictions exempt ADUs under 750 sq ft from impact fees per state law.
0 locationsADU Owner Occupancy
Whether the property owner must live on-site to operate an ADU, deed-restriction requirements, and recent state-law changes lifting owner-occupancy rules.
0 locationsADU Rental Restrictions
Whether an ADU can be rented short-term (Airbnb), 30-day minimums, separate rental licenses, and long-term lease requirements.
0 locationsShed Rules
When you need a permit for a storage shed, maximum sizes that are exempt from permits, and how far sheds must be from property lines.
657 locationsGarage Conversions
Rules for converting a garage into living space, including whether you need to replace the lost parking and what building codes apply.
635 locationsCarport Rules
Permit and setback requirements for building a carport, including size limits and whether carports count toward lot coverage maximums.
440 locationsTiny Homes
Zoning rules for tiny houses on wheels and foundations, including minimum square footage requirements and where they can be placed.
463 locationsAccessory Structures by City
Jump to accessory structures rules for a specific city.
Accessory Structures Rankings
Seasonal Accessory Structures Guides
Accessory Structures by State
States with the most accessory structures data on file.
Expert Guides
Most ADU-Friendly Cities in America (2026)
Accessory dwelling units are transforming housing across the country. These cities make it easiest to build one on your property.
Can You Build an ADU? What the Rules Actually Say
Accessory dwelling units are one of the hottest topics in residential development, but the rules governing them are a maze of state mandates and local regulations. Here is what you need to know.
Urban vs Suburban: How Local Rules Actually Differ
City centers and suburbs often operate under the same municipal code, but how those rules play out in practice can be dramatically different. Here is where the gaps show up most.
California ADU Rules: What Homeowners Need to Know (2026)
California leads the nation in ADU-friendly legislation. Here is what homeowners need to know about building an accessory dwelling unit in 2026.
Washington State ADU and Backyard Cottage Rules (2026)
Washington has embraced ADU-friendly legislation. Here is what homeowners need to know about building an accessory dwelling unit in 2026.
ADU and Granny Flat Rules in 2026: What Has Changed
Accessory dwelling unit regulations are evolving fast. Here is what homeowners need to know about building an ADU under the latest rules.