Tex. Water Code § 26.0136

(a) The commission is the agency with primary responsibility for implementation of water quality management functions, including enforcement actions, within the state. Water quality management functions shall be oriented on a watershed basis in consideration of the priorities identified by river authorities and basin steering committees. The commission by rule shall coordinate the water quality responsibilities of river authorities within each watershed and shall, where appropriate, delegate water quality functions to local governments under Section 26.175 of this code. The State Soil and Water Conservation Board shall coordinate and administer all programs for abating agricultural or silvicultural nonpoint source pollution, as provided by Section 201.026, Agriculture Code.

(b) Nothing in this section is intended to enlarge, diminish, or supersede the water quality powers, including enforcement authority, authorized by law for river authorities, the State Soil and Water Conservation Board, and local governments. Nothing in this section is intended to enlarge, diminish, or supersede the responsibilities of the Texas Agricultural Extension Service and the Texas Agricultural Experiment Station to conduct educational programs and research regarding nonpoint source pollution and related water resource and water quality matters.

(c) The commission shall establish rules to make the optimum use of state and federal funding and grant programs related to water quality programs of the commission.

(d) In this section, "river authority" has the meaning assigned by Section 26.0135(i) of this code.