(a) An act or proceeding of a district, its governing body, or any local government corporation, development corporation, or nonprofit corporation of the district is conclusively presumed, as of the date it occurred, to be valid and to have occurred in accordance with all applicable statutes and ordinances if:
(1) the second anniversary of the effective date of the act or proceeding has expired; and
(2) a lawsuit to annul or invalidate the act or proceeding has not been filed on or before that second anniversary.
(b) This section does not apply to:
(1) an act or proceeding that was void at the time it occurred;
(2) an act or proceeding that, under a statute of this state or the United States, was a misdemeanor or felony at the time the act or proceeding occurred; or
(3) a matter that on the second anniversary of the effective date of the act or proceeding:
(A) is involved in litigation if the litigation ultimately results in the matter being held invalid by a final court judgment; or
(B) has been held invalid by a final court judgment.
Official text of the Texas Water Code as published by the Texas Legislative Council.