Tex. Civil Practice and Remedies Code § 101.056: DISCRETIONARY POWERS.

This chapter does not apply to a claim based on:

(1) the failure of a governmental unit to perform an act that the unit is not required by law to perform; or

(2) a governmental unit's decision not to perform an act or on its failure to make a decision on the performance or nonperformance of an act if the law leaves the performance or nonperformance of the act to the discretion of the governmental unit.

Acts 1985, 69th Leg., ch. 959, Sec. 1, eff. Sept. 1, 1985.