UNREASONABLE PREFERENCE OR PREJUDICE PROHIBITED.
Tex. UTIL Code § 104.004.
in effectA gas utility may not:
(1) grant an unreasonable preference or advantage concerning rates or services to a person in a classification;
(2) subject a person in a classification to an unreasonable prejudice or disadvantage concerning rates or services; or
(3) establish or maintain an unreasonable difference concerning rates of services between localities or between classes of service.