Tex. Utilities Code § 184.052

(a) The commission shall adopt rules governing billing systems or methods used by an apartment house owner to prorate or allocate among tenants central system utility costs or nonsubmetered master metered utility service costs.

(b) In addition to other appropriate safeguards for a tenant of an apartment house, a rule adopted under this section must require that:

(1) a rental agreement contain:

(A) a clear written description of the method of computing the allocation of central system utilities or nonsubmetered master metered utilities for the apartment house; and

(B) a statement of the average apartment unit monthly bill for all apartment units for any allocation of central system utilities' costs or nonsubmetered master metered utility service costs for the previous calendar year; and

(2) the apartment house owner:

(A) not impose a charge on a tenant in excess of the actual charge imposed on the owner for utility consumption by the apartment house; and

(B) maintain adequate records, including utility bills and records concerning the central system utility or nonsubmetered master metered utility service consumption of the apartment house, the charges assessed by the utility, and the allocation of central system utilities' costs or nonsubmetered master metered utility service costs to the tenants and make the records available for inspection by the tenants during normal business hours.

(c) A rule adopted under this section has the same effect as a rule adopted under Title 2, and an owner, operator, or manager of an apartment house subject to this subchapter is subject to enforcement under Sections 15.021, 15.022, 15.028, 15.029, 15.030, 15.031, 15.032, and 15.033.