Tex. Water Code § 49.2122

(a) Notwithstanding any other law, a district may establish different charges, fees, rentals, or deposits among classes of customers that are based on any factor the district considers appropriate, including:

(1) the similarity of the type of customer to other customers in the class, including:

(A) residential;

(B) commercial;

(C) industrial;

(D) apartment;

(E) rental housing;

(F) irrigation;

(G) homeowner associations;

(H) builder;

(I) out-of-district;

(J) nonprofit organization; and

(K) any other type of customer as determined by the district;

(2) the type of services provided to the customer class;

(3) the cost of facilities, operations, and administrative services to provide service to a particular class of customer, including additional costs to the district for security, recreational facilities, or fire protection paid from other revenues; and

(4) the total revenues, including ad valorem tax revenues and connection fees, received by the district from a class of customers relative to the cost of service to the class of customers.

(a-1) Notwithstanding Subsection (a), a district that provides nonsubmetered master metered utility service, as defined by Section 13.087(a)(1), to a recreational vehicle park, as defined by Section 13.087(a)(3):

(1) shall determine the rates for that service on the same basis the district uses to determine the rates for other commercial businesses that serve transient customers and receive nonsubmetered master metered utility service from the district; and

(2) may not charge a person who owns or operates a recreational vehicle park that receives nonsubmetered master metered utility service from the district an administrative fee for the services provided.

(b) A district is presumed to have weighed and considered appropriate factors and to have properly established charges, fees, rentals, and deposits absent a showing that the district acted arbitrarily and capriciously.