Q. How do you cite the Texas Administrative Code both in the bibliography and the in text citation?

These links may help:

•  How do I cite a state statute or law in the APA style? https://rasmussen.libanswers.com/faq/41374
• This is for federal -State statutes should be similar http://blog.apastyle.org/apastyle/2013/02/writing-references-for-federal-statutes.html
• There is a blog entry and in the comments there is q&a about the Texas Administrative Code (TAC). http://blog.apastyle.org/apastyle/2010/01/the-generic-reference-where.htm