Tex. Parks & Wild. Code § 21.011
The department shall require every bidder, except administrators of state funds, to include with their bid an exchange or cashier's check for an amount the department considers adequate as a forfeit guaranteeing acceptance of and payment for all bonds covered by the bid.
Acts 1975, 64th Leg., p. 1405, ch. 545, Sec. 1, eff. Sept. 1, 1975.