30 Tex. Admin. Code § 304.44
Any person purporting to act for any water right holder, in regard to diversion, use, or impoundment of state water, or payment of a watermaster assessment, or for a contractual buyer, in regard to diversion, use, or impoundment of state water, shall submit to the watermaster a document signed by such right holder confirming such authority and specifying the duration of such authority.
Source Note:The provisions of this §304.44 adopted to be effective August 5, 1988, 13 TexReg 3639.