The Texas Administrative Code contains all state agency rules in Texas after they have been published in the Texas Register. There are 16 titles, each representing a subject.
The Texas Secretary of State's website has a free version of the Texas Administrative Code online. It is also available on the subscription databases Westlaw, and LexisNexis.
Texas Register
The Railroad Commission is the oldest regulatory agency in the state of Texas. Originally established to regulate the railroads, the Railroad Commission of Texas is now perhaps best known for regulating Texas' oil and gas industry.