What's Required in Columbus
- Permitted 'by-right' on residential lots as of late 2025
- Maximum size 1,000 sq ft or 65% of the principal unit (whichever is greater)
- Maximum height is 25 feet or the height of the primary building
- Independent cooking, sleeping, and sanitation facilities must be included
- Historic districts (German Village, etc.) still require Commission approval
- Lot coverage limit of 65% total including ADU and primary unit
How Much Does an ADU Permit Cost in Columbus?
Budget $1,100–$2,500 for the Columbus permit itself (project-based), issued by the City of Columbus Department of Building and Zoning Services — but treat that as the entry fee, not the total. ADUs are full dwelling units, so the permit stack usually includes building, electrical, plumbing, and mechanical trade permits, plus plan review. One local note: uses 'New Construction' residential base fee ($1,100) plus zoning and trade permits. Get an itemized fee estimate from the department before finalizing your budget; the spread between a simple conversion and a new detached build is wide.
ADU Size Limits and Zoning Rules in Columbus
Before drawing plans, check the two gates that sink most ADU projects: size and zoning. Size ceilings vary by lot and ADU type (attached, detached, or conversion), so confirm your specific configuration. Setbacks, height limits, and utility connections layer on top of those rules. The City of Columbus Department of Building and Zoning Services can confirm what your specific lot allows — worth doing before you pay for architectural drawings rather than after.
How to Get a ADU Permit in Columbus
Step 1: Zoning Verification
Confirm lot coverage and setbacks for ADU eligibility.
Step 2: Professional Plans
Develop IRC-compliant construction drawings.
Step 3: Portal Submission
Submit 'Residential New Construction' for the ADU unit.
Step 4: Fee Payment
Pay building ($1,100) and zoning ($150–$300) fees online.
Step 5: Full Inspections
Schedule full sequence: Foundation, Framing, Trades, and Final.