22 Tex. Admin. Code § 107.15
In computing time periods prescribed by these rules, or by order of the agency, the day of the act, event or default on which the designated period of time begins to run is not included. The last day of the period is included, unless it is a Saturday, Sunday or legal holiday, in which case the time period will end on the next day that the agency is open.
Source Note:The provisions of this §107.15 adopted to be effective January 1, 1976; amended to be effective November 30, 1999, 24 TexReg 10541.