Mississippi Accessory Dwelling Unit Building Code Standards

Under Mississippi Code Section 17-2-1, all counties and municipalities must adopt one of the last three editions of the International Building Code or International Residential Code as their State Uniform Construction Code unless they formally opted out before November 30, 2014. ADUs constructed within adopting jurisdictions must satisfy IRC structural, electrical, plumbing, mechanical, and energy requirements. The state does not mandate ADU permission itself, leaving zoning approval, owner-occupancy, and density rules to local discretion. Counties may impose stricter standards but cannot fall below the state minimum building code.

Construction without required permits or in violation of adopted building codes can result in stop-work orders, fines, mandatory remediation, and denial of certificate of occupancy.