CHAPTER 39
REQUIREMENTS FOR PROPERLY PLUGGING ABANDONED WELLS
567—39.1(455B) Purpose. The purpose of this chapter is to implement Iowa Code section 455B.190 by providing a schedule and required procedures for the proper plugging of abandoned wells to protect the groundwater by permanently sealing off contamination to individual aquifers.
567—39.2(455B) Applicability. These rules govern the proper plugging of abandoned wells. Some examples of types of wells covered by these rules are those accessing groundwater (withdrawing water from or injecting water into the groundwater) and can include, but are not limited to: public and nonpublic water wells, test wells, observation wells, monitoring wells, agricultural drainage wells, heat pump recirculation wells, and cooling water wells. Some examples of types of wells or subsurface structures not covered by these rules include: small diameter (2” or less) test holes, observation wells or monitoring wells installed for a limited time which can be sealed by withdrawal of the casing and allowing the hole to collapse; soil borings; septic tanks; underground storage tanks; and cisterns if not used for accessing groundwater. For additional guidance and background information, refer to “Guidelines for Plugging
Abandoned Water Wells,” Technical Information Series 15, Geological Survey Bureau, Iowa Department of Natural Resources, 1987.
567—39.3(455B) Definitions.
“Abandoned well” means a water well which is no longer in use or which is in such a state of disrepair that continued use for the purpose of accessing water is unsafe or impractical.
“Agricultural lime” means all calcium and magnesium products sold for agricultural purposes in the carbonate form, not including quicklime or hydrated lime, of a size comparable with that of crushed stone, gravel or pea gravel.
“Approved” means accepted or acceptable under an applicable specification stated or cited in these rules.
“Aquifer” means a water-bearing geologic formation capable of yielding a usable quantity of water to a well or spring.
“Bentonite” means a naturally occurring highly plastic, colloidal clay composed largely of the mineral montmorillonite which expands upon wetting.
“Bentonite grout (or slurry)” means a mixture of 10 percent processed bentonite (by weight) and water which is free of contaminants, turbidity and settleable solids.
“Bentonite pellets” means a form of processed bentonite which can be used directly for sealing applications in well plugging operations.
“Bentonite products” means the forms of bentonite which can be used for sealing material in wells, including graded bentonite, bentonite pellets and bentonite grout.
“Capped” means the application of a layer of sealing material at the top of the well casing.
“Casing” means a tubular retaining structure installed in an excavated hole to maintain the well opening.
“Certified well contractor” means a well contractor certified by the department in accordance with 567—Chapter 82.
“Class 1 well” means a well 100 feet or less in depth and 18 inches or more in diameter.
“Class 2 well” means a well more than 100 feet in depth or less than 18 inches in diameter or a bedrock well. Bedrock wells include:
1. Wells completed in a single confined aquifer;
2. Wells completed in a single unconfined aquifer; and
3. Wells completed in multiple aquifers.
“Class 3 well” means a sandpoint well or a well 50 feet or less in depth constructed by joining a screened drive point with lengths of pipe and driving the assembly into a shallow sand and gravel aquifer.
“Concrete” means a mixture of one sack (94 pounds) of Portland cement, up to but not exceeding an equal amount by volume of sand and up to but not exceeding an equal amount by volume of gravel or crushed stone and not more than six gallons of water which is free of contaminants, turbidity and settleable solids.
“Confined aquifer” means an aquifer in which the groundwater is under pressure greater than atmospheric pressure. The static water level in a well tapping a confined aquifer rises to a level above the top of the aquifer.
“Crushed stone” means stone (predominantly limestone), crushed and well graded, with 100
percent passing a 1-inch sieve, in accordance with the 1984 edition of Iowa department of transportation specification No. 4120.04 for Class A crushed stone.
“Department” means the department of natural resources created under Iowa Code section 455A.2.
“Designated agent” means a person other than the state, designated by a county board of supervisors to review and confirm that a well has been property plugged.
“Director” means the director of the department.
“Filling materials” means agricultural lime, soil, sand, gravel, crushed stone, rock and pea gravel used to occupy space between and below sealing materials in abandoned wells being plugged.
“Frost pit” means a sunken area located directly over or within 4 feet of a well and used to house the equipment for discharging water from a well into the water system.
“Graded bentonite” means bentonite which is crushed and sized for pouring and easy handling. Like processed bentonite, it swells when hydrated with water and will form a plastic, essentially impermeable mass.
“Gravel” means stone screened from river sand or quarried, with 100 percent passing a ¾-inch sieve, in accordance with the 1984 edition of the Iowa department of transportation specification No. 4120.02 for Class B gravel.
“Groundwater” means any water beneath the surface of the earth.
“Grout” means, for the purposes of this chapter, a fluid mixture of cement and water (neat cement); sand, cement and water (sand cement grout); or bentonite and water (bentonite grout or slurry) of a consistency that can be forced through a pipe and placed as required.
“Limestone” means sedimentary rock which contains greater than 50 percent calcium carbonate and has a strong reaction with hydrochloric acid (HCL).
“Neat cement” means a mixture of one sack (94 pounds) of Portland cement to not more than six gallons of water which is free from contaminants, turbidity or settleable solids. Bentonite up to 2 percent by weight of cement may be added to reduce shrinkage.
“Owner” means the titleholder of the land where an abandoned well is located.
“Pea gravel” means gravel sized from 1/8 inch to 3/8 inch in diameter.
“Plug” means the closure of an abandoned well with plugging materials by procedures which will permanently seal the well from contamination by surface drainage and permanently seal off the well from contamination into an aquifer. This involves the proper application of filling and sealing materials.
“Processed bentonite” means bentonite which has been kiln dried and processed into pellets for direct use in well sealing applications or into powder or coarse granules for use in bentonite grout for sealing.
“Rock” means stone screened from river sand or quarried, free of debris, foreign matter and any toxic or agricultural chemical residue, up to 2½ inches in diameter.
“Sand” means clean, medium-textured quartz (concrete sand) and shall be at least 25 percent with diameters between 2.0 and 0.25 mm, less than 35 percent with diameters between 0.25 and 0.05 mm and less than 5 percent with diameters between 0.002 and 0.05 mm.
“Sand cement grout” means a mixture of one sack (94 pounds) of Portland cement, an equal amount by volume of sand and not more than six gallons of water which is free from contaminants, turbidity and settleable solids.
“Sandpoint well” means a small diameter water well constructed by joining a screened drive point with lengths of pipe and driving the assembly into a shallow sand and gravel aquifer.
“Sealing” means the proper placement of sealing materials into an abandoned well to seal off flow into, out of or between aquifers.
“Sealing materials” means bentonite products. Sealing materials may also include neat cement, sand cement grout and concrete.
“Standby well” means a water well which is temporarily taken out of service with the expectation of being returned to service at a future date.
“Static water level” means the water level in a water well or aquifer when the well is not flowing or being pumped; sometimes referred to as the water line. The static water level for an abandoned well is determined just prior to commencing plugging operations.
“Tremie pipe” means a device, usually a small diameter pipe, that carries grouting materials to the bottom of the hole and which allows pressure grouting from the bottom up without introduction of air pockets.
“Unconfined aquifer” means an aquifer in which the static water level does not rise above the top of the aquifer, i.e., the pressure of the water in the aquifer is approximately equal to that of the atmosphere.
“Water well” means an excavation that is drilled, cored, bored, augered, washed, driven, dug, jetted or otherwise constructed for accessing groundwater.
567—39.4(455B) Forms. The following form is currently in use: Abandoned Water Well Plugging Record. 542-1226.
567—39.5(455B) Abandoned well plugging schedule.
39.5(1) Class 1 wells abandoned prior to April 25, 1990, must be properly plugged by July 1, 1995.
39.5(2) Class 2 and 3 wells abandoned prior to April 25, 1990, must be properly plugged by July 1, 2000.
39.5(3) Wells near contamination sources. All classes of wells abandoned prior to April 25, 1990, and located less than 200 feet from an active well supplying potable water or located less than 660 feet from a point source of potential contamination which may include, but is not limited to, industrial waste sites; uncontrolled hazardous waste sites; petroleum storage areas; hazardous waste treatment, storage, or disposal areas; agricultural chemical storage areas; animal feedlots; and wastewater treatment facilities must be properly plugged by July 1, 1993.
39.5(4) Wells abandoned after April 25, 1990. All classes of wells which are abandoned on or after April 25, 1990, must be properly plugged within 90 days of the date of abandonment.
567—39.6(455B) Abandoned well owner responsibilities.
39.6(1) Plugging requirements. The owner is responsible for ensuring the abandoned well is
plugged pursuant to this chapter.
39.6(2) Record. It is the responsibility of the owner to certify, on DNR Form 542-1226 “Abandoned Water Well Plugging Record,” that an abandoned well has been plugged in accordance with the requirements and time schedule contained in this chapter. This report must include confirmation of the well plugging by the designated agent for the county or a certified well contractor. Within 30 calendar days of the date the plugging was completed, the owner shall submit to the department a copy of DNR Form 542-1226.
567—39.7(455B) Abandoned well plugging materials.
39.7(1) Sealing materials. Approved sealing materials are bentonite products (graded bentonite, bentonite pellets and bentonite grout), neat cement, sand cement grout and concrete.
39.7(2) Filling materials. Approved filling materials include agricultural lime, soil, sand, pea
gravel, gravel and crushed stone. The filling materials shall be free of debris, foreign matter and any toxic or agricultural chemical residue. Filling materials are not required for well plugging.
567—39.8(455B) Abandoned well plugging procedures.
39.8(1) Freedom from obstructions. Abandoned wells must be checked before they are plugged in order to ensure there are no obstructions that may interfere with plugging operations. Drop pipes, check valves, pumps, and other obstructions shall be removed if practical.
39.8(2) Class 1 wells. These wells may be plugged by pouring filling and sealing materials from the top of the well or by using tremie pipes, except for sand cement grout or concrete placed below the static water level, which must be placed by tremie pipe or dump bailer.
Filling materials of sand, gravel, crushed stone, rock, pea gravel or agricultural lime shall be placed up to 1 foot below the static water level; soils are not permitted below the static water level due to naturally occurring bacteriological, organic and inorganic contaminants. A minimum of 1 foot of bentonite pellets, graded bentonite or neat cement shall be placed on top of the filling material up to the static water level as a seal. Sand cement grout or concrete applied with a tremie pipe or dump bailer also may be used on top of the filling material up to the static water level and in standing water above the static water level to act as a seal. Filling material may then be added up to 4 feet below the ground surface.
It is preferable that the filling materials be omitted and that sealing materials be used to fill the entire well up to 4 feet below the ground surface. Sand cement grout or concrete shall be placed with a tremie pipe or dump bailer when used below the static water level.
The casing pipe and any curbing, frost pipe or pump house structure shall be removed to a depth of 4 feet below the ground surface and shall be capped by a minimum of 1 foot of bentonite pellets, graded bentonite, neat cement, sand cement grout or concrete. The cap shall extend 6 or more inches beyond the outside diameter of the top of the remaining well casing and shall terminate 3 feet below the ground surface. The remaining 3 feet (below the ground surface) shall then be backfilled with soil and graded so that surface water is directed away from the abandoned well location.
39.8(3) Class 2 wells other than bedrock wells. If the details of well construction are unknown or obstructions that may interfere with well plugging cannot be removed, the well shall be tremied full of neat cement or bentonite grout up to 4 feet below the ground surface. If bentonite grout is used from the static water level to the top of the well, it should be capped by neat cement, sand cement grout or concrete terminating 4 feet below the ground surface.
Filling material consisting of sand, gravel, crushed stone, pea gravel or agricultural lime shall be placed in the bottom of the well up to 4 feet below the static water level. A minimum of 4 feet of sealing materials consisting of any bentonite products or neat cement shall be added above the filling material up to the original static water level. If bentonite grout or neat cement is used, it shall be placed by tremie pipe. If graded bentonite or bentonite pellets are used, they may be added by pouring in place and agitating to avoid bridging. Sealing materials shall be added above the static water level up to 4 feet below the ground surface. If bentonite grout is used from the static water level to the top of the well, it should be capped by neat cement, sand cement grout or concrete terminating 4 feet below the ground surface.
It is preferable that the filling materials be omitted and that sealing materials be used to fill the entire well up to 4 feet below the ground surface.
Casing pipe and any curbing, frost pit or pump house structure shall be removed to a depth of 4 feet below the ground surface. The remaining 4 feet shall then be backfilled with soil and graded so that surface water is directed away from the abandoned well location.
39.8(4) Class 2 bedrock wells. If the details of well construction are unknown or obstructions that may interfere with well plugging cannot be removed, the well shall be tremied full of neat cement or bentonite grout up to 4 feet below the ground surface. If bentonite grout is used from the static water level to the top of the well, it should be capped by neat cement, sand cement grout or concrete terminating 4 feet below the ground surface.
The casing pipe and any curbing, frost pit or pump house structure shall be removed to a depth of 4 feet below the ground surface. The remaining 4 feet shall then be backfilled with soil and the surface shall then be graded to divert water away from the abandoned well location.
a. Bedrock wells completed in a single confined aquifer. Before proceeding to plug the well, a bridge plug or packer shall be placed at or below the bottom of the casing to stop the flow of water where the pressure in the confined aquifer causes the water to flow from the well to the surface. In such cases, filling materials shall be placed in the lower portion of the well before the bridge plug or packer is set.
Filling material consisting of pea gravel, crushed stone, gravel or agricultural lime shall be placed from the bottom of the well up to 10 feet below the bottom of the casing or confining layer, whichever is lower. Sealing materials consisting of any bentonite products, sand cement grout or neat cement shall be placed from the top of the filling material to at least 10 feet above the bottom of the casing or confining layer or to the static water level, whichever is higher. If bentonite grout, neat cement or sand cement grout is used, it shall be placed by tremie pipe. If graded bentonite or bentonite pellets are used, they shall be added by pouring in place and agitating to avoid bridging. The casing shall then be filled up to 4 feet below the ground surface with sealing materials. If bentonite grout is used from the static water level to the top of the well, it should be capped by neat cement, sand cement grout or concrete terminating 4 feet below the ground surface.
It is preferable that the filling materials be omitted and that approved sealing materials be used to fill the entire well up to 4 feet below the ground surface.
The casing pipe and any curbing, frost pit or pump house structure shall be removed to a depth of 4 feet below the ground surface. The remaining 4 feet shall then be backfilled with soil and graded so that surface water is directed away from the abandoned well location.
b. Bedrock wells completed in a single unconfined aquifer. The plugging procedure for these wells is the same as for bedrock wells completed in a single confined aquifer except that a bridge plug or packer is not required to stop the flow of water since this problem will not exist in this type of well.
c. Bedrock wells completed in multiple aquifers. For the lowest aquifer, filling material consisting of pea gravel, crushed stone, gravel or agricultural lime shall be placed from the bottom of the well up to 10 feet below the bottom of the casing or confining layer, whichever is lower. Neat cement tremied in place shall then be placed as a sealing material on top of the fill and extend upward at least 20 feet. Sealing materials shall then be placed in at least the top 10 feet of each subsequent aquifer and extend at least 10 feet into the confining layer or casing above. The same type of filling materials and sealing procedures shall apply for each subsequent aquifer. Filling material may be placed from the top of the uppermost aquifer seal up to the static water level of the well. The casing shall then be filled with approved sealing or filling materials to 4 feet below the ground surface. If bentonite grout is used from the static water level to the top of the well, it should be capped by neat cement, sand cement grout, or
concrete terminating 4 feet below the ground surface.
It is preferable that the filling materials be omitted and approved sealing materials be used to fill the entire well up to 4 feet below the ground surface. Sand cement grout or concrete shall be applied with a tremie pipe or dump bailer when applied below the static water level.
The casing pipe and any curbing, frost pit or pump house structure shall be removed to a depth of 4 feet below the ground surface. The remaining 4 feet shall then be backfilled with soil and graded so that surface water is directed away from the abandoned well location.
39.8(5) Class 3 wells. The preferred method of plugging a sandpoint well is to pull the casing and sandpoint out of the ground, allowing the hole to collapse and fill. If the sandpoint and casing cannot be extracted, they shall be tremied full of neat cement or completely sealed with bentonite products.
The casing pipe and any curbing, frost pit or pump house structure shall be removed to a depth of 4 feet below the ground surface. The remaining 4 feet shall then be backfilled with soil and graded so that surface water is directed away from the abandoned well location.
567—39.9(455B) Designated agent. A county’s board of supervisors shall appoint an individual
to be responsible to review and confirm an abandoned well to be properly plugged as required by 567—39.8(455B) and authorized by Iowa Code section 455B.190. The designation is effective upon notification to the department by the chairperson of the board of supervisors. This notification will include the identity of the designated agent and the length of appointment. Changes in a designated agent will require new notification by the chairperson to the department.