1 The State of Texas Clean Water Act 303(d) list comprises surface-water bodies in Texas identified by the Texas Natural Resource Conservation Commission as impaired (do not meet applicable water-quality standards) or threatened (are not expected to meet applicable standards in the near future). Section 303(d) of the Federal Clean Water Act (together with related regulations) requires each State to assess the quality of its surface waters and to develop water-quality improvement strategies for impaired and threatened waters.