Tex. Water Code § 15.317

(a) The price of the sale or transfer of a state facility acquired on or subsequent to September 1, 1981, other than a facility acquired under a contract with the United States, shall be the sum of the direct cost of acquisition, plus an amount of interest calculated by multiplying the lending rate in effect at the date of acquisition by the amount of board money disbursed for the acquisition times the number of years and fraction of a year from the date or dates of the disbursement of funds to the date or dates of the sale or transfer of the state facility, plus the board's cost of operating and maintaining the facility from the date of acquisition to the date of sale or transfer, less any payments received by the board from the lease of the facility or the sale of water from it.

(b) The purchaser of the board's interest in a state facility shall also assume, to the extent disclosed by the board at or before the sale, any and all direct, conditional, or contingent liabilities of the board attributed to the project in direct relation to the percentage of the project acquired by the purchaser.