30 Tex. Admin. Code § 297.19
The commission may grant a permit for a limited term of years when it determines that inadequate water is available in the source of supply on a perpetual basis to satisfy an application but that adequate water is available on a limited basis due to the underutilization of existing water rights in the source of supply. The commission may grant a permit under this section for an aquifer storage and retrieval project as defined in §297.1 of this title (relating to Definitions).
Source Note:The provisions of this §297.19 adopted to be effective May 29, 1986, 11 TexReg 2330; amended to be effective June 28, 1996, 21 TexReg 5442.