(a) The commission shall require from an applicant for a new or amended water right the formulation and submission of a water conservation plan and the adoption of reasonable water conservation measures, as defined by Subdivision (8)(B), § 11.002, of this code.
(b) The commission shall require the holder of an existing permit, certified filing, or certificate of adjudication for the appropriation of surface water in the amount of 1,000 acre-feet a year or more for municipal, industrial, and other uses, and 10,000 acre-feet a year or more for irrigation uses, to develop, submit, and implement a water conservation plan, consistent with the appropriate approved regional water plan, that adopts reasonable water conservation measures as defined by Subdivision (8)(B), § 11.002, of this code. The requirement for a water conservation plan under this section shall not result in the need for an amendment to an existing permit, certified filing, or certificate of adjudication.

(c) Beginning May 1, 2005, all water conservation plans required under this section must include specific, quantified 5-year and 10-year targets for water savings. The entity preparing the plan shall establish the targets. Targets must include goals for water loss programs and goals for municipal use in gallons per capita per day.
(d) The commission and the board jointly shall identify quantified target goals for water conservation that water suppliers and other entities may use as guidelines in preparing water conservation plans. Goals established under this subsection are not enforceable requirements.
(e) The commission and board jointly shall develop model water conservation programs for different types of water suppliers that suggest best management practices for achieving the highest practicable levels of water conservation and efficiency achievable for each specific type of water supplier.
(f) The commission shall adopt rules:
(1) establishing criteria and deadlines for submission of water conservation plans, including any required amendments, and for submission of implementation reports; and
(2) requiring the methodology and guidance for calculating water use and conservation developed under § 16.403 to be used in the water conservation plans required by this section.
(g) At a minimum, rules adopted under Subsection (f)(2) must require an entity to report the most detailed level of municipal water use data currently available to the entity. The commission may not adopt a rule that requires an entity to report municipal water use data that is more detailed than the entity’s billing system is capable of producing.