Section 0400-45-09-.16 - WELL ABANDONMENT(1) The driller or person holding a license for well closure shall backfill and close any newly drilled water well not intended for use in which casing has not been installed or from which casing has been removed, within fifteen (15) days after the drill rig leaves the site. The driller shall take all steps necessary to maintain safety around the site until the closure process is completed. Prior to closing any such well, the driller shall:(a) Remove all equipment or material that may obstruct access to the bottom of the well;(b) Check the entire depth of the well for obstructions that may interfere with sealing operations and remove them, and(c) Thoroughly chlorinate the well prior to sealing by the addition of sufficient quantities of liquid bleach or dry hypochlorite granules to produce a free chlorine residual of twenty-five (25) parts per million (ppm).(2) Except as provided in paragraphs (3), (4), (5) and (6) of this rule water well plugging and closure shall be accomplished by a licensed driller by the following methods: (a) For uncased water wells, a cement grout or bentonite as defined in subparagraph (c) of this paragraph or other grout material approved by the Department shall be placed in the well bore from two feet below land surface to a minimum of twenty-five (25) feet below land surface. Native soil may be used to backfill the borehole from land surface to two feet below land surface or the driller may use cement or bentonite to land surface. The well bore twenty-five (25) feet below land surface shall be filled with either bentonite, cement grout, clean crushed stone one half inch in diameter or less, well cuttings, puddled clay, sand or combined mixture of any of these listed materials. Backfill shall remain level with land surface.(b) For water wells with a minimum of nineteen feet of casing installed, a surface plug consisting of either cement grout or bentonite as defined in subparagraph (c) of this paragraph shall be placed in the well bore from land surface to a minimum of five (5) feet below land surface. An additional seal of cement grout or bentonite as defined in subparagraph (c) of this paragraph shall also be placed in the well bore for a minimum length of ten (10) feet. The top of this ten (10) foot seal shall either be located within twenty (20) feet below the bottom of the casing or at the top of the well screen or perforated pipe. The remaining well bore or casing shall be backfilled with either bentonite, cement grout, clean crushed stone one half inch in diameter or less, well cuttings, puddled clay, sand, or combined mixture of any of these listed materials. Surface casing may be terminated two (2) feet below land surface and native soil may be placed in the well bore from two feet to land surface provided that the upper surface plug of cement or bentonite grout is placed in the borehole from two to seven feet below land surface. Backfill shall remain level with land surface.(c) The grout material used in the plugging and abandonment of a water well shall consist of a grout material approved by the Department or a mixture consisting of Portland Class A cement or quick setting cement in a ratio of not over six (6.0) gallons of water per ninety-four (94) pound sack of cement, or a high solids bentonite grout with a minimum of 20% solids and a weight of no less than nine and two tenths (9.2) pounds per gallon as measured by a standard mud balance. The use of bentonite, in chip or tablet form, ranging in size from one-quarter inch (1/4") to three-quarters (3/4) of an inch will be allowed as an alternate seal to slurry grouting. The bentonite shall be mixed and applied in accordance with the manufacturer's recommendations. The use of low solids bentonite drilling clay (designed for use as a drilling fluid to form a filter cake on the side walls of the borehole and to increase viscosity of water) is prohibited for use as a grout or sealing material except as an additive. If bentonite is used as a sealing material only bentonite grout, bentonite tablets, or bentonite chips, approved by the National Sanitation Foundation (NSF) or American National Standards Institute (ANSI) certified parties as meeting NSF product standard 60 or 61 shall be approved by the Department as appropriate grouting or sealing material.(d) Placement of the backfill material shall be done in such a way that there are no bridges or gaps in the well bore. The top of the backfill material shall remain level with land surface.(3) Wells extending into more than one aquifer shall be filled and sealed in such a way that exchange of water from one aquifer to another is prevented.(4) The sealing of flowing wells shall be accomplished only after the wells have been treated to reduce the flow to zero. This may be accomplished by introducing high specific gravity fluids which are approved for use in potable water systems into the bottom of the well bore and continuing until the flow ceases.(5) The driller or a person holding a license for well closure may submit a written petition for an alternative method of well abandonment. Any alternate method of filling and sealing a well shall be submitted to the Director for review and written approval prior to sealing a well by such method. In an emergency or in exceptional instances, the Department will respond to a verbal request provided the applicant submits a written application within ten (10) days of the verbal application.(6) Hand dug water wells greater than twelve inch in diameter without steel or plastic casing and less than sixty (60) feet in depth may be abandoned by a landowner, or the following individuals licensed in Tennessee: licensed engineers, licensed professional geologists, licensed building contractors, licensed pump installers, county environmentalists, or environmental specialists for the state of Tennessee. They must all follow the construction standards for the closure of a hand dug well. The landowner should contact the Division of Water Resources or a licensed driller prior to closing a hand dug well for additional technical assistance. The person, other than the landowner closing the hand dug well is responsible for submitting the well closure report for the hand dug well. A landowner who does the well closure is not required by law to complete a well closure report: however it is recommended that the landowner submit a letter to the Division of Water Resources similar to information submitted on a well closure report. The information serves as a public record of the landowners' compliance with state well construction standards and will be important information for land appraisals and property transfer arrangements. No matter who does the job, the landowner is ultimately responsible for the closure of a hand dug well.(7) Hand dug water wells may be closed by using the following procedures: (a) Thoroughly chlorinate the well prior to sealing by the addition of sufficient quantities of liquid bleach or dry hypochlorite granules to produce a free chlorine residual of twenty-five (25) parts per million within the entire well.(b) Cement grout or bentonite as defined in subparagraph (2)(c) of this rule must be used from five feet to two feet below land surface to place a barrier for the well. The remaining annular space from two feet to land surface may be filled with native soil or cement. Backfill must remain level with land surface.(c) Construction debris, trash or wood are prohibitive materials and must never be used during the well closure process.(d) Native soil material, gravel less than one inch or less in diameter, cement or bentonite may be used as well closure material from five feet below land surface to the total depth of the well.(8) All well closure reports shall include a diagram showing the location and distance in feet of the closed well from one specific landmark and septic system or sewer systems on the property.(9) Well Abandonment-Existing Wells with Obstructions (a) Existing wells required to be closed for which no well construction report is on file and/or those that are partially filled or obstructed with soil, rock, construction debris or other materials must be cleaned out inside the well down to a minimum depth of twenty-five (25) feet below land surface to allow for proper sealing of the upper terminus of the well.1. If the well does not open up and remains filled below twenty-five (25) feet, the well shall be backfilled and sealed from twenty-five (25) feet to land surface with a cement grout or bentonite as defined in subparagraph (2)(c) of this rule.2. If the well opens up below twenty-five (25) feet while cleaning, the well shall be backfilled from its lowermost open depth to twenty-five (25) feet below land surface with either cement grout, bentonite, clean crushed stone one-half (1/2) inch diameter or less, well cuttings, puddled clay, sand or a combined mixture of any of these materials. Cement grout or bentonite as defined in subparagraph (2)(c) of this rule shall be used to backfill the well from twenty-five (25) feet to land surface.(b) If the grading or elevation changes are expected at the site, native soil or crushed rock can be used to backfill the well from land surface to two (2) feet below land surface.(c) The driller will be required to file a well closure report with the Department within sixty (60) days of the completion of the well abandonment.Tenn. Comp. R. & Regs. 0400-45-09-.16
Original rule filed October 16, 2012; effective January 14, 2013. Rule renumbered from 1200-04-09. Amendment filed June 19, 2015; effective 9/17/2015.Authority: T.C.A. §§ 69-10-101 et seq. and 4-5-201 et seq.