Tex. Loc. Gov't Code § 155.002

(a) A request for a payroll deduction must:

(1) be in writing;

(2) be submitted to the county auditor; and

(3) state the amount to be deducted and the entity to which the amount is to be transferred.

(b) A request remains in effect until the county auditor receives a written notice of revocation signed by the employee.

(c) A payroll deduction may not exceed the amount stated in the request.