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Underground Injection Wells in Region 5

There are over 75,000 known injection wells of all well classes in Region 5. The number and type operating in each state differ based on many factors such as geology and industrial or commercial needs.

• Class I Underground Injection Wells in Region 5 for example operate in Illinois, Indiana, Michigan, and Ohio where there are underground formations capable of containing large volumes of wastewater.
• Class II wells operate in Illinois, Indiana, Michigan, and Ohio where there are oil and gas reserves.
• Class III wells operate only in Michigan and Ohio which have sufficient ore deposits.
• Class IV and V wells can be found in every state, while Minnesota and Wisconsin have only Class V wells.
• Also for Class V wells, inventories may be incomplete due to their vast number and due to shifting priorities and funding and staffing resources unique to each state. Also see Managing Class V wells in Region 5.

Well Inventories

• Region 5 General Well Inventory
  • Illinois
  • Indiana
  • Michigan
  • Minnesota
  • Ohio
  • Wisconsin
• Tribal Lands
• Region 5 Tribal well inventory (MI, MN, & WI)

Well Classes

1. Industrial & municipal waste disposal wells (Class I)
2. Oil- and gas-related injection wells (Class II)
3. Mining wells (Class III)
4. Shallow hazardous and radioactive injection wells (Class IV)
5. Non-hazardous injection wells (Class V)
6. Geologic sequestration wells (Class VI)

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Region 5 General Well Inventory

Data last updated

State	Class I Wells Hazardous	Class I Wells Non-Hazardous	Class II Wells	Class III Sites	Class III Wells	Class IV Wells	Class V Wells
Illinois	3	2	7,843	0	0	0	16,644
Indiana	4	24	2,091	0	0	0	8,729
Michigan	9	21	1,460	5	46	0	8,934
Minnesota	0	0	0	0	0	0	2,744
Ohio	10	0	2,455	4	54	0	22,461
Wisconsin	0	0	0	0	0	0	1,662
Region 5 Total	26	47	13,849	9	100	0	61,174

Subcategories of Class V wells

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Illinois

• Class I, II, and V injection wells operate in Illinois.
• There are 5 Class I wells (3 hazardous and 2 non-hazardous), 7843 Class II wells, and 16,644 Class V wells in Illinois.
• Industries in Illinois with Class I wells are associated with steel production and cheese product waste. These wells mostly inject into the Mt. Simon sandstone. The Class I wells in this state operate in Tuscola, Illinois in Douglas County and in Hennepin, Illinois in Putnam County.
• Class II wells can be found where oil and gas reserves are found in the state. Most oil and gas production occurs in the southern part of the state and in 40 of the 102 counties in Illinois. The oil producing area of Illinois is part of a gelogic structure or province known as the Illinois Basin. The Illinois Basin underlies most of Illinois and extends into southwest Indiana and Northwest Kentucky. In Illinois, it comprises deeply buried unminable coal seams, depleted oil and gas reservoirs, and deep, brine-filled rock formations.
• There is a potential for Class IV wells to exist in this state although these wells are banned unless part of an EPA approved cleanup.
• Many types of Class V wells exist in Illinois. The vast majority of these are aquifer remediation wells, storm water drainage wells, and domestic wastewater disposal wells of which most are large capacity septic systems. Class III injection wells do not exist in this state.
• There are also carbon sequestration wells in this state operating in Decatur, Illinois.
• The Illinois EPA regulates Class I, III, IV, and V wells in Illinois and the Illinois Department of Natural Resources regulates Class II wells in this state.

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Indiana

• Class I, II, and V injection wells operate in this state.
• There are 28 Class I wells (4 hazardous and 24 non-hazardous), 2,091 Class II wells, and 8,729 Class V wells in Indiana.
• Class IV wells are banned unless part of an EPA approved cleanup.
• The EPA Region 5 Office regulates Class I, III, IV, and V wells and the Indiana Department of Natural Resources regulates Class II wells.

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Michigan

• All classes of wells (I-V) can be found in Michigan.
• There are 30 Class I wells (9 hazardous and 21 non-hazardous), 1,460 Class II wells, 46 Class III wells (5 Sites), and 8,934 Class V wells in Michigan.
• There are spent-brine return flow wells or 5X16 wells in Michigan. These wells are used to re-inject spent brine into the same formation from which it was withdrawn after extraction of halogens or their salts. Michigan is the only state where these wells are known.
• In Michigan, there are three companies that use Class III wells. These three companies inject into the Salina Group which has an average thickness of 900 to 2000 feet. The well inventory chart lists the number of active Class III wells and sites. The map below shows geographic locations of the Class III facilities in Michigan.
  • Morton Salt uses Class III wells as part of their salt mining operation in Manistee County.
  • Mosaic uses Class III wells as part of their potassium mining operation in Osceola County.
  • Cargill uses Class III wells as part of their salt mining operation in St. Clair County.
• Class IV wells are banned unless part of an EPA approved cleanup.
• The Region 5 EPA UIC program is responsible for regulating all wells in this state.

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Minnesota

• Only Class V wells operate in this state. The state's geology is unsuitable for development of the other well types. As such, there are no Class I, II, or III wells in Minnesota.
• There are 2,744 Class V wells in Minnesota.
• The Region 5 EPA UIC program is responsible for regulating all wells in this state.

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Ohio

• All five classes of injection wells operate in Ohio.
• There are 10 Class I wells (all hazardous), 2,455 Class II wells, 54 Class III wells (4 sites), and 22,461 Class V wells in Ohio.
• Contact these agencies for more information about injection wells in Ohio:
  • The Ohio Environmental Protection Agency regulates Class I, IV, and V wells.
  • The Ohio Department of Natural Resources regulates Class II wells and, under agreement with the Ohio EPA, all Class III wells.
  • Also, the Ohio DNR has more information about industrial waste disposal in Ohio.

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Wisconsin

• There are 1,662 Class V wells operating in Wisconsin. This is the only well type that operate in this state. The state's geology is unsuitable for development of other deeper well types.
• A great majority of these wells are large capacity septic systems for domestic wastewater disposal and storm water drainage wells.
• Wisconsin law bans all injection well practices.
• See subcategories of Class V wells to find out the various types of Class V wells that operate in Wisconsin.
• The Wisconsin Department of Natural Resources is responsible for regulating all well types in Wisconsin except those found on tribal lands.
• The EPA Region 5 UIC program is responsible for regulating all wells on tribal lands in this state.
• About wells on tribal Lands.

About Wells on Tribal Lands

• In Region 5, there are tribal lands in Michigan, Minnesota, and Wisconsin.
• There are a total of 14 Class II wells and 668 Class V wells on tribal lands in Region 5.
• The Class II wells are primarily located on the Saginaw (Isabella) tribal lands in Michigan.
• Class V wells are present throughout all tribal lands in the aforementioned states. Various subcategories of Class V wells operate on tribal lands.
• There are no Class I or III wells on tribal lands.
• Class IV wells are banned unless part of an EPA approved cleanup.
• The table below breaks out the number and type of wells found on land owned by each tribe.
• The Region 5 EPA UIC program is responsible for regulating all wells on tribal lands in Region 5. For more information about Region 5's interaction with tribes and UIC activities on tribal lands in Region 5 see controlling injection wells on tribal lands.

Region 5 Tribal Well Inventory (Michigan, Minnesota, & Wisconsin)

Tribe	Class I Wells Hazardous	Class I Wells Non-Hazardous	Class II Wells	Class III Sites	Class III Wells	Class IV Wells	Class V Wells
Michigan
Bay Mills/S.I.	0	0	0	0	0	0	16
Grand Traverse	0	0	0	0	0	0	8
Hannahville	0	0	0	0	0	0	7
Huron Potawatomi	0	0	0	0	0	0	1
Lac Vieux Desert	0	0	0	0	0	0	5
Keweenah Bay (L'Anse/Ontonagon)	0	0	0	0	0	0	23
Little River Band of Ottawa	0	0	0	0	0	0	1
Little Traverse Band of Odawa	0	0	0	0	0	0	10
Matchebenashewish (Gun Lake) Potawatomi	0	0	0	0	0	0	1
Pokagon Potawatomi	0	0	0	0	0	0	2
Saginaw (Isabella)	0	0	14	0	0	0	24
Sault Ste. Marie	0	0	0	0	0	0	11
Tribe	Class I Wells Hazardous	Class I Wells Non-Hazardous	Class II Wells	Class III Sites	Class III Wells	Class IV Wells	Class V Wells
Minnesota
Bois Forte Chippewa	0	0	0	0	0	0	19
Fond du Lac Chippewa	0	0	0	0	0	0	10
Grand Portage Chippewa	0	0	0	0	0	0	4
Leech Lake Chippewa	0	0	0	0	0	0	35
Lower Sioux	0	0	0	0	0	0	9
Mille Lacs Chippewa	0	0	0	0	0	0	47
Prairie Island	0	0	0	0	0	0	8
Red Lake Chippewa	0	0	0	0	0	0	20
Sandy Lake	0	0	0	0	0	0	0
Shakopee Mdewakanton Sioux	0	0	0	0	0	0	1
Upper Sioux	0	0	0	0	0	0	12
White Earth Chippewa	0	0	0	0	0	0	113
Tribe	Class I Wells Hazardous	Class I Wells Non-Hazardous	Class II Wells	Class III Sites	Class III Wells	Class IV Wells	Class V Wells
Wisconsin
Bad River Lake Superior Chippewa	0	0	0	0	0	0	2
Forest Co. Potawatomi	0	0	0	0	0	0	0
Ho-Chunk	0	0	0	0	0	0	4
Lac Courte Oreilles	0	0	0	0	0	0	112
Lac Du Flambeau Chippewa	0	0	0	0	0	0	55
Menominee	0	0	0	0	0	0	36
Oneida	0	0	0	0	0	0	3
Red Cliff Lake Superior Chippewa	0	0	0	0	0	0	6
Saint Croix Chippewa	0	0	0	0	0	0	50
Sokaogon Chippewa	0	0	0	0	0	0	6
Stockbridge Munsee	0	0	0	0	0	0	7
Tribal Total	0	0	14	0	0	0	668

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