Texas
Texas is a home rule state. Building code adoption takes place at the local level. However, Texas’ municipal building, residential, fire, plumbing, mechanical, fuel gas and swimming pool and spa codes are promulgated through legislation and found in state statute. A listing of these codes is referenced at Texas State Law Library at https://www.sll.texas.gov/law-legislation/texas/building-codes/. Municipalities can make local amendments to these respective codes as well as adopt later editions of them at will.
The Texas Department of Licensing and Regulation, Texas Industrialized Building Code Council currently adopts the 2015 IBC, IRC, IFGC, IMC, IPC, IECC and IEBC. https://www.tdlr.texas.gov/ihb/codes.htm
The Texas Department of Licensing and Regulation Air Conditioning and Refrigeration Contractors program currently adopts the 2018 IMC, IRC, IFGC. RULE §75.110
The Texas State Board of Plumbing Examiners currently adopts the 2018 IPC, IRC, and IFGC. TSBPE Administrative Rules
The energy conservation code is promulgated through the Texas State Energy Conservation Office (SECO) by administrative rule. A municipality or county may establish procedures to adopt local amendments to Texas’ commercial and residential energy codes. However, such amendments may not result in less stringent energy efficiency requirements in non-attainment and affected counties. To obtain more detailed information on commercial and residential energy codes adopted in Texas, contact SECO. See https://comptroller.texas.gov/programs/seco/code/adoption.php.