Tex. Health and Safety Code § 383.023: TERMS.

Bonds issued under this chapter must mature serially or otherwise not more than 40 years after they are issued. The bonds may:

(1) bear interest at a rate and be sold at a price or under terms that the governing body of the issuer determines to be the most advantageous reasonably obtainable;

(2) be made callable before maturity at times and prices prescribed in the resolution authorizing the bonds;

(3) be in coupon form; and

(4) be registrable as to principal or as to principal and interest.

Acts 1989, 71st Leg., ch. 678, Sec. 1, eff. Sept. 1, 1989.