(a) It is the responsibility of the owner or operator to close a Class V well which is to be permanently discontinued or abandoned under standards set forth in this section unless the well must comply with §331.136 of this title (relating to Closure Standards for Motor Vehicle Waste Disposal Wells, Large Capacity Septic Systems, Large Capacity Cesspools, Subsurface Fluid Distribution Systems, and Drywells). The well must be closed in a manner that complies with §331.5 of this title (relating to Prevention of Pollution) and 40 Code of Federal Regulations (CFR) §144.12 ("prohibition of movement of fluid into underground sources of drinking water," effective June 2, 1987 at 48 FR 20676). Any contaminated soil, gravel, sludge, liquids, or other materials removed from or adjacent to the well must be managed in accordance with Chapter 350 of this title (relating to Texas Risk Reduction Program), and all other applicable federal, state, and local regulations and requirements.
(b) Closure shall be accomplished by removing all of the removable casing and the entire well shall be pressure filled via a tremie pipe with cement from bottom to the land surface.
(c) As an alternative to the procedure in subsection (b) of this section, if a Class V well is not completed through zones containing undesirable groundwater, water that is injurious to human health and the environment or water that can cause pollution to land or other waters, the well may be filled with fine sand, clay, or heavy mud followed by a cement plug extending from land surface to a depth of not less than ten feet below the land surface.
(d) As an alternative to the procedure in subsection (b) of this section, if a Class V well is completed through zones containing undesirable groundwater, water that is injurious to human health and the environment or water that can cause pollution to land or other waters, either the zone(s) containing undesirable groundwater or the fresh groundwater zone(s) shall be isolated with cement plugs and the remainder of the wellbore filled with bentonite grout (9.1 pounds per gallon mud or more) followed by a cement plug extending from land surface to a depth of not less than ten feet below the land surface.
(e) It is the responsibility of the owner or operator to ensure that temporary injection points are pressure grouted from the bottom of the well to the land surface, and the injection point is sealed to prevent the migration of fluids into underground sources of drinking water.
(f) It is the responsibility of the owner or operator to close improved sinkholes in a manner that prohibits the movement of contaminated fluids into underground sources of drinking water, in compliance with §331.5 of this title, and 40 CFR §144.12 (as amended through June 2, 1987 at 48 FR 20676); and to demonstrate that any fluids released through the closed well will meet the primary maximum contaminant levels (MCLs) for drinking water contained in 40 CFR Part 141, and other appropriate health-based standards at the point of injection.

Source Note: The provisions of this §331.133 adopted to be effective May 13, 1986, 11 TexReg 1988; amended to be effective June 25, 2000, 25 TexReg 5908; amended to be effective July 12, 2001, 26 TexReg 5019