Tex. Spec. Dist. Code § 6902.207
(a) Bonds not payable wholly from ad valorem taxes may be additionally secured, at the discretion of the board, by a deed of trust or mortgage lien on physical property of the district, franchises, easements, water rights and appropriation permits, leases, contracts, and all rights appurtenant to the property, vesting in the trustee power to:
(b) A purchaser under a sale under the deed of trust lien, if one is given:
Added by Acts 2007, 80th Leg., R.S., Ch. 920 (H.B. 3166), Sec. 1.06, eff. April 1, 2009.