40B-3.531. Abandoned Well Plugging

(1) All abandoned water wells, abandoned artesian wells, and wells that no longer serve an intended purpose shall be plugged using all or a combination of the following materials and methods, unless an alternative abandonment plan is approved in advance by the District in accordance with Section 373.326(1), F.S.: (a) Neat cement grout or a bentonite slurry applied from the bottom of the originally drilled depth of the well to the upper well terminus using the tremie method. (b) Bentonite chip material introduced into the well as follows: 1. The material is screened at land surface to remove fine particles prior to introduction into the well; 2. The material is only placed below the static water level; and 3. The material is introduced into the well in a manner that prevents bridging. (c) Clean sand or aggregate introduced into the well as follows: 1. The material is used after significant loss of grout has occurred or is anticipated; 2. The integrity of any confining unit is maintained; 3. The material is introduced into the well in a manner that prevents bridging; and 4. The material is not used to plug any portion of the well casing. (2) In addition to the provisions set forth in subsection 40B-3.531(1), F.A.C., the following methods are authorized for well abandonments: (a) Wells completed or plugged to a depth of less than 40 feet may be abandoned by pouring neat cement grout through a tremie until return is observed at land surface; (b) Piezometers or monitoring wells that do not penetrate any consolidated or confining units may be abandoned by the removal of the entire length of well casing and screen, and plugging the portion of the borehole that does not naturally infill as set forth in this section. (3) All well abandonments shall be finished with no less than a one-foot thickness of neat cement grout at the top of the remaining borehole or within the upper well terminus, regardless of whether the upper well terminus is buried post-plugging.