ADU Rules in Columbus, OH (2026)

Whether Columbus, OH permits accessory dwelling units (ADUs) has not been confirmed from an official source. ADUs — also called granny flats, in-law units, or secondary suites — are secondary housing units on a single-family or multifamily lot. Contact the local building department at (614) 645-7433 to verify current ADU rules before proceeding, as regulations may have changed since this data was last reviewed.

ADU Size Limits

ADU Size Limits in Columbus: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.

Permit Fees

ADU Permit Fees in Columbus: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.

Permit Timeline

Columbus ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Phone: (614) 645-7433.

Setback Requirements

ADU Setback Requirements in Columbus: Front setback: Exempt from fronting and rear yard requirements, per C.C. 3332.19 and 3332.27, respectively.. Side setback: must meet the minimum required side yards of the underlying zoning district. Rear setback: Exempt from fronting and rear yard requirements, per C.C. 3332.19 and 3332.27, respectively.. One detached ADU may occupy up to 45 percent of the total rear yard of the principal dwelling. Two separate or adjoining detached ADUs may occupy up to 55 percent of the total rear yard.

Parking Requirements

Parking Requirements: Parking requirements have not been confirmed — see official source.

Restrictions & Requirements

• •Maximum one ADU per single-family lot in R-1, R-2, R-3 zones
• •ADU must be on same lot as primary single-family dwelling
• •ADU cannot be separately conveyed or sold apart from the primary lot
• •Total impervious coverage limits by zone apply
• •ADU must have separate entrance independent from primary dwelling entrance
• •Alley access strongly encouraged for rear-yard ADU placement

How Many ADUs Are Allowed?

Number of ADUs Allowed in Columbus: Single-family lots: 1. Multifamily properties: ADUs may be added to any multiple-dwelling development subject to a five percent increase in the maximum number of units allowed per the area district requirements.. One ADU may be added to a lot containing a single-unit dwelling in all residential districts within Chapter 3332, except as specified below for the R-2F and R-4 districts.

Single-Family Lots

1 · Verified July 14, 2026 · Source

Multifamily Properties

ADUs may be added to any multiple-dwelling development subject to a five percent increase in the maximum number of units allowed per the area district requirements. · Verified July 14, 2026 · Source

Statewide Preemption

Frequently Asked Questions