Tex. Water Aux. Laws § 7868

After registration of said bonds by the Comptroller, the directors shall sell the same on the best terms and for the best price possible, not less than their face value and the accrued interest thereon; or they may exchange bonds in payment of the contract price for work to be done for the use and benefit of said district. All moneys received from the sale of bonds shall be forthwith paid to the district depository.