Decommissioning of Abandoned or Unused Water Wells and Boreholes

Decommissioning of Abandoned or Unused Water Wells and Boreholes. A. Applicability (1) Except as stated in paragraph B. below, the standards for decommissioning abandoned or unused water wells and boreholes apply to all abandoned water wells and to all boreholes that penetrate water bearing strata or are greater than twenty-five (25) feet in depth including potable water wells, agricultural wells, monitoring wells, observation wells, dewatering wells, relief wells, saline or brackish water withdrawal wells, contaminant recovery wells, heat pump water supply wells and closed loop system holes, industrial supply wells, rig supply wells, geotechnical boreholes, cathodic protection wells and pilot boreholes. (2) All wells and boreholes that penetrate water bearing stratum with a depth of 25 feet, or greater, below land surface must properly be decommissioned by a water well contractor licensed by MDEQ. Water wells less than 25 feet in depth below land surface may be plugged by someone other than a licensed water well contractor. However, the same procedures and reporting requirements apply regardless of who plugs the well. (3) If approved and accepted in writing by MDEQ, properly cased and sealed wells may be provided with a locking cover capable of preventing the entrance of contaminants and used as monitoring wells or observation wells in lieu of abandonment. If the use of an observation or monitoring well is later discontinued by MDEQ, the landowner/permittee shall be responsible for having the well properly decommissioned by a licensed water well contractor. B. Exemptions - Exemption from this regulation does not relieve the owner of the responsibility for identifying and complying with other applicable local, state, and federal regulations. The following types of wells and boreholes are exempt from decommissioning requirements set forth in this regulation: (1) Saline water wells associated with enhanced oil and gas recovery operation, brine withdrawal wells, and other types of on-site oil and gas well holes, including Class II wells regulated under the Resource Conservation and Recovery Act (RCRA), 42 U.S.C. Sections 6901, et seq.; (2) Class I, III, IV and V injection wells regulated under the Resource Conservation and Recovery Act (RCRA), 42 U.S.C. Sections 6901, et seq.; and (3) Geotechnical boreholes less than twenty-five (25) feet in depth that do not penetrate water bearing strata and boreholes drilled in planned roadbed construction areas where the natural overburden will be removed to within twenty-five (25) feet of the bottom of the hole. C. Types of Abandoned or Unused Wells – A water well may be considered by MDEQ to have been abandoned if its use has been permanently discontinued; if the well has not been used in the preceding 12 months (except for established rotations of pumping equipment between wells related to crop irrigation and instances where the owner has notified MDEQ of an anticipated longer period of nonuse after which the well will be placed back in service.); if the pumping equipment has been removed (except for established rotations of pumping equipment between wells related to crop irrigation); or if the well cannot be repaired. Rig supply holes, geotechnical boreholes, pilot holes, and dewatering holes are considered abandoned immediately upon completion of the project phase for which they are drilled, unless the well is an integral part of the continued operation of the project, such as a pressure relief well or a permanently used dewatering well. D. Time allowed for plugging - Rig supply wells, pilot holes, and geotechnical boreholes shall be plugged within 30 days after abandonment or cessation of use. All other holes shall be plugged within 180 days after abandonment or cessation of use. E. Decommissioning Forms -- Abandonment and plugging of water wells and boreholes shall be reported on a decommissioning form approved by and made available from MDEQ. The person or contractor who plugs an abandoned water well or borehole shall submit the decommissioning form to MDEQ within 30 days after completion of the plugging. For irrigation wells located in the MRVA, a copy of the form shall be submitted to YMD at the same time the original is submitted to MDEQ. Reporting the abandonment and plugging of multiple water wells and/or boreholes on one form may be permissible, with prior approval from MDEQ, provided the same decommissioning procedure was used and the location of each water well and/or borehole is clearly identified. F. Decommissioning Procedures – The following procedures shall be followed in the decommissioning of any water well or borehole for which decommissioning is required under this regulation: (1) Grout for all holes shall consist of neat cement, cement grout, cement bentonite mixture (5-8% bentonite), or bentonite. Bentonite pellets may be added under free-fall conditions for depths not exceeding twenty-five (25) feet, providing pellets are placed in layers not more than five (5) feet deep and tamped into place after addition of each layer. Granulated or palletized bentonite may be placed to greater depths if introduced through a tremie pipe. Free-fall addition of other types of grout from the surface is prohibited; (2) Obstructions shall be removed from the well casing; (3) If there is reason to question the physical integrity of the well casing because of the age of the well or the material used for the casing, or there are no records to indicate that the annular space was grouted properly during construction of the well, the driller shall consult with MDEQ before plugging the well. In such instances, MDEQ may require that the casing be perforated to allow the introduction of grout into cavities or voids that may have formed outside the casing; or may require that the casing be removed from the hole prior to grouting; (4) For abandoned water wells in agricultural fields, the casing shall be cut off and removed down to a minimum depth of three feet below land surface. After grouting, the excavation shall be filled with compacted soil. In other areas, the casing shall be cut off and removed at least down to the ground surface elevation. MDEQ may authorize alternate methods of abandonment and/or abandonment by other than a licensed water well contractor, provided the results will meet the intent of the regulations. Only detailed written requests to utilize an alternate method of abandonment or to abandon a well without utilizing a licensed water well contractor shall be considered for approval. If approved, MDEQ will provide written authorization to the requestor. (5) Abandoned water wells or boreholes shall be sealed from the bottom of the hole to ground surface using a grout as described in paragraph 1 above. (6) MDEQ may authorize alternate methods of abandonment and/or abandonment by other than a licensed water well contractor, provided the results will meet the intent of the regulations. Only detailed written requests to utilize an alternate method of abandonment or to abandon a well without utilizing a licensed water well contractor shall be considered for approval. If approved, MDEQ will provide written authorization to the requestor.