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119 South Fillmore Mt. Ayr, IA 50854 View Location

Well Plugging and Rehabilitation

Contamination of our groundwater is most common through old, abandoned wells and poorly constructed wells. The groundwater moves through the soil, and any well that taps into this vital resource is a potential channel for pollution.

  • The Grants-to-Counties Program provides cost-share assistance to plug and correct well construction problems that can allow contaminants to enter the groundwater supply.
  • Many wells can be rehabilitated.

Common Well Integrity Issues

  • Abandoned wells often are not adequately covered. Small animals can enter the well, drown and remain floating in the water. The polluted well then has direct contact with water used for everyday drinking and bathing.
  • Poorly constructed wells can be a channel for pollution.
  • Large-diameter brick wells can allow contamination to enter at all levels of the well.

Well Plugging Process

Well rehabilitation generally involves pumping standing water from the well prior to filling it. This eliminates the mess of overflow and reduces the risk of bridging.

Fill Sand

Fill sand is used in large diameter wells to reduce settling that occurs over time. The bottom layer is sand is brought up to the static water level.

Bentonite Clay

Bentonite clay is used to create a seal or plug in the well to prevent surface water from following the pathway of the abandoned well to the groundwater. In wells with a diameter of four feet or more, the bentonite is replaced with concrete. On small diameter wells, bentonite or concrete slurry is used to flow into limited space.

Casing

More sand is added after the sealing material is in place. When the well has been filled up to about four feet below the natural grade, the casing is knocked in. Soil may be used to fill to the top. Road rock (limestone) is often used in place of sand.

Certified Well Pluggers

For the DNR’s list of people certified to plug wells, go to Iowa DNR. Click on “Reports” and select “Well Diggers,” “Pump Installers” or “Well Pluggers.”  This list is not an endorsement of any specific well drillers or plugging contractors, nor is it meant to be exclusive of any other certified well drillers or plugging contractors.