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Underground Injection Wells in Our Region
Underground injection wells are divided into five classes in Title 40 of the Code of Federal Regulations (40 CFR)
Part 144, Underground Injection Control Program Section 144.6 and
Part 146, Underground Injection Control Program: Criteria and Standards
Section 146.5.
View the current Inventory of Injection Wells in Region 5
Typical Deep Well Construction and Operation (Class I, Class II, Class III and Class 5X16)
The casing string, which extends from the ground surface to at least the top of the injection zone, must be adequately cemented to the surface to preclude the movement of fluids into and between USDWs due to injection operations. As additional protection, injection takes place through tubing which is set within the steel casing. The space between the casing string and the tubing is sealed at the top by the wellhead and at the bottom of the injection tubing by a device called a packer in such a way that the pressure within this space can be monitored and leaks detected. Injection wells are pressure-tested initially after completion to ensure that they have mechanical integrity and are tested periodically thereafter to ensure that they maintain mechanical integrity. If the well should fail a mechanical integrity demonstration, it will be shut down immediately until corrective actions have been taken and the well has been brought back into compliance. Any work performed on the well which requires moving and/or the removal of the tubing or packer must be followed by a mechanical integrity test before authorization to resume injection will be given. The conditions of the permit limit the injection pressure to ensure the safe operation of the well. Monthly reports of the pressure and flow rates must be submitted to our office for review.
Class I Wells
View the map of Class I wells in Michigan and Indiana.
View the list of Class I wells in Region 5 (Illinois, Indiana, Michigan and Ohio).
For more information about Class I wells, you can look at the U.S. EPA Headquarters webpage devoted to Class I wells.
Class II Wells
View the map of Class II wells in Michigan.
For more information about Class II wells, you can look at the U.S. EPA Headquarters webpage devoted to Class II wells.
Class III Wells
View the map of Class III wells in Michigan.
For more information about Class III wells, you can look at the U.S. EPA Headquarters webpage devoted to Class III wells.
Class V Wells
All injection wells not included in Classes I, II, III or IV. Most Class V wells are shallow disposal systems but a few are deep wells which do not fit into Class I, II or III. In particular, Spent-Brine Return Flow Wells (5X16) are used to re-inject spent brine into the same formation from which it was withdrawn after extraction of halogens or their salts. In Region 5, they are found in Michigan. Of the shallow Class V wells, three types of particular concern are
- Industrial Waste Disposal Wells (5W20) are industrial process water and water disposal wells, used to dispose of a wide variety of wastes and wastewaters from industrial, commercial or utililty processes.
- Motor Vehicle Waste Disposal Wells (MVWDW, 5X28) wells are automobile service station disposal wells, usually repair bay floor drains which discharge into the ground. These wells are banned in most places.
- Large Capacity Cesspools (5W10) accept domestic sanitary waste and which have open bottoms and sometimes perforated sides. These wells are banned.
For more information about Class V wells, you can look at the Region 5 Shallow Disposal System web page and the U.S. EPA Headquarters webpage devoted to Class V wells.