Sec. 55.005.  UNREASONABLE PREFERENCE OR PREJUDICE CONCERNING SERVICE PROHIBITED.  In providing a service to persons in a classification, a public utility may not:
(1)  grant an unreasonable preference or advantage to a person in the classification;  or
(2)  subject a person in the classification to an unreasonable prejudice or disadvantage.
Acts 1997, 75th Leg., ch. 166, Sec. 1, eff. Sept. 1, 1997.