Tex. Local Government Code § 501.208

(a) The principal of and interest on any bonds issued by a corporation shall be secured by a pledge of the revenues and receipts derived by the corporation from the lease or sale of the project financed by the bonds or from the loan made by the corporation with respect to the project financed or refinanced by the bonds.

(b) As security for the payment of the principal of and interest on any bonds issued by a corporation and any agreements made in connection with the issuance of bonds, the corporation may:

(1) mortgage and pledge any or all of the corporation's projects or any part of a project, including the project financed or refinanced and any enlargements of and additions to the project, owned before or acquired after the time of the mortgage or pledge; and

(2) assign any mortgage and repledge any security conveyed to the corporation to secure any loan made by the corporation, and pledge the revenues and receipts from the assigned mortgage or security.

(c) The resolution authorizing the issuance of bonds and any mortgage covering all or part of the project financed may include any agreement or provision that the board of directors considers advisable and not in conflict with this subtitle and that relates to:

(1) the maintenance of the project covered by the bonds or mortgage;

(2) the fixing and collection of rents;

(3) purchase price payments;

(4) loan payments;

(5) the creation and maintenance of special funds from those revenues; or

(6) the rights and remedies available in the event of a default.

(d) A mortgage to secure bonds may also provide that, in the event of a default in the payment of the bonds or a violation of another agreement contained in the mortgage, the mortgage may be foreclosed and the mortgaged property may be sold in any manner permitted by law. The mortgage may provide that a trustee under the mortgage or the holder of any of the bonds secured by the mortgage may purchase property at a foreclosure sale if the trustee or holder is the highest bidder.

(e) A pledge, agreement, or mortgage made for the benefit or security of any of the corporation's bonds continues in effect until the principal of and interest on the bonds benefited or secured by the pledge, agreement, or mortgage have been fully paid.