Topeka, KS Accessory Structures: ADU Permits (2026)

Topeka treats accessory dwelling units as accessory residential uses on lots with a principal single-family dwelling, regulated under Chapter 18 (Zoning) of the Topeka Code of Ordinances and administered by Planning and Development Services (620 SE Madison St, Topeka). The accessory dwelling must be subordinate in scale to the primary residence, comply with the rear- and side-yard setbacks of the underlying R-1 / R-2 zoning district (commonly 5 ft side and 25 ft rear in standard single-family districts), and observe accessory-structure height limits typically capped at 25 ft or the height of the principal dwelling, whichever is less. Building permit applications go to Development Services (620 SE Madison) and require site plan, floor plan, structural sheets, and separate trade applications for electrical, plumbing, and mechanical work. Construction must comply with the 2018 International Residential Code as adopted by the State of Kansas through the State Department of Administration's Building Code Office, with any City of Topeka amendments. Topeka sits in a high tornado-risk zone — IRC wind-load design (ASCE 7) requires construction for 115 mph wind speed, and storm-shelter ratings (ICC-500) are increasingly used. Detached ADUs sharing utilities with the principal dwelling avoid new service connections; otherwise Topeka Water and the local sanitary sewer authority assess connection charges. KSA 12-741 et seq. delegates zoning authority to cities; there is no Kansas statewide ADU preemption analogous to California's AB 671/881.