[bluGill]

I'm not sure what codes are in Texas, but I can tell you in MN the housing codes are designed nationally to cover CA earthquakes and Florida Hurricanes even though both are not factors. Of course those codes also cover insulation which the other two states don't really need as much of..

[gamblor956]

Housing codes are adopted at the municipal or state level. There is no mandatory "national" building code in the U.S., though there is a "model" building code at the national level upon which the state and local building codes are based. (https://localhousingsolutions.org/housing-policy-library/hou...)

Specifically, Texas just uses the ICC's IRC, while California has the California Building Standards Code, which has additional requirements to account for our many earthquakes (https://peer.berkeley.edu/sites/default/files/peer2019-05_ss...).