Unplugged abandoned wells are a safety, health, and environmental threat.
EGLE recommends that property owners hire registered well drilling contractors to plug abandoned wells. Registered well drillers have the specialized training and equipment necessary to properly plug abandoned wells.
Properly plugging the old well is the preferred option. Plugging the well protects the drinking water aquifer and limits the property owner's liability for ground water contamination.
The Groundwater Quality Control Act, Part 127, 1978 PA 368 (state well code) requires that:
“A well that is abandoned when municipal water is installed shall be plugged.”
Some county, local, and municipal jurisdictions have ordinances that prohibit the retention of private wells when structures are connected to municipal water service.
To retain the existing well for irrigation, car washing, or other uses, it must be restored to operational condition.
Plumbing changes are required to physically separate the structure’s domestic water piping served by the municipal water system, from the piping connected to the well.
A cross connection inspection and approval from the public water utility, the plumbing inspector, or the local health department is required when water service is initiated.
Where existing wells will be retained for non-potable purposes, well construction upgrades are recommended, but are not mandatory.
The property owner is ultimately responsible for plugging an abandoned water well. An unsuccessful water well (commonly known as a “dry hole”) is normally plugged by the well drilling contractor.
A property owner may plug a well only at his/her residence. A well drilling contractor or his/her employee may plug a well at any residence, farm, industry, business, or other public water supply.
Farms often have associated, but not necessarily, contiguous properties that have structures served by water wells. These outlying farm wells are considered the same as the farmer’s residential well and may be plugged by the owner.
Begin by searching for water well drilling records or old billing statements that show well depth and well location. Information of this type on your well may be available from the contractor who drilled or serviced the well, or the local health department.
If there are no records available for your well, you can look for signs on your property such as:
Metal detectors may be used to find buried steel well casings. First, locate where the old water line exited the home or building. From this point, survey the ground with the metal detector moving away from the structure. Use a marker to designate the location of any “readings” you get. Usually, well casings will be 4 to 5 feet below grade and will be located between 3 and 25 feet from the home. Neighbors and senior citizens who have lived in the area for a long time are an excellent source of information. They often know where old wells are located. If you take advantage of their input you may save yourself a lot of work.
Pumps, drop pipe, pump rods, packers, wire, check valves, and all other debris or obstructions must be removed from the well before plugging. Due to the equipment necessary, this often requires the services of a registered well drilling contractor. Failure to remove obstructions from the well can result in void spaces in the column of plugging material. Following removal of the obstructions, the depth and diameter of the well must be measured before plugging to allow the drilling contractor or well owner to calculate the amount of plugging material necessary to fill the entire depth of the well.
Well type and site geology affect the requirements for plugging abandoned water wells. Each well type has specific plugging requirements.
These large (12 to 48 inch diameter) wells are made of cement crock, brick, stone, or tile. A six (6) inch layer of bentonite chips or pellets shall be placed at the bottom of the well. The remainder of the well shall be plugged by placing clean soil backfill* layers that are not more than ten (10) feet thick, with a six (6) inch layer of bentonite chips between backfill layers. The upper three (3) to four (4) feet of stone, brick, cement crock, or curbing must be broken up and removed. A final six (6) inch layer of bentonite must be placed three (3) feet below finish grade, then the remainder of the hole backfilled and crowned to prevent settling and ponding of water over the old well. Clean, dry soil backfill may be loam, clay, silt, or sand obtained from commercial sources or from the site.
*Clean backfill may not contain trash, wood, roots, sod, construction debris, or chemical contaminants.
Bentonite grout slurry, neat cement slurry*, or dry bentonite chips or pellets may be used to plug wells with screens in sand and gravel formations. All slurry grouts must be placed using a tremie pipe which runs to the bottom of the well. The slurry may be pumped or poured using a funnel into the tremie pipe. Plugging is complete when the grout appears at the surface. The tremie pipe should be removed after or during the plugging process.
*Neat cement slurry is a mixture of one 94 pound bag of Portland cement and not more than six (6) gallons of water.
Because of their unique characteristics, flowing wells should only be plugged by registered well drilling contractors. Neat cement must be used to plug flowing wells. Its heavy slurry weight is needed to initially overcome the artesian pressure of flowing wells, and then to provide a solidified permanent seal.
These small diameter wells (normally 1-1/4 inch diameter) are plugged by carefully dropping bentonite chips or pellets into the top of the well casing. Another method is to pour a slurry of neat cement through a funnel and tremie pipe extending to the bottom of the well. If bentonite chips are used, a
hardware cloth screen (1/4 inch mesh) shall be used to remove any fine bentonite particles before the chips are poured into the well. If they are not removed, they will swell upon contacting water, bridge in the upper part of the well, and will prevent effective plugging of the lower part of the well.
Neat cement must be used when plugging bedrock wells. A pump and a tremie pipe (run to the bottom of the well) are used to deliver the grout to the bottom of the well. The tremie pipe is removed as the neat cement is pumped into the well or after thick cement appears at the surface. Bedrock wells should be plugged by registered well drilling contractors.
