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Subcategories of Class V Wells

Class V wells exist in all six Region 5 six states.

There are over 61,000 Class V wells of many different types (See general Region 5 well inventory for a state-by-state breakout).

Most Class V wells are shallow, but some are deeper, such as the 5X16 injection wells in Michigan. These wells re-inject spent brine.

Experimental Class V wells can also inject at greater depths.

The most endangering types of Class V wells are shallow and inject harmful fluids into or above ground water. These are the Motor Vehicle Waste Disposal Wells (5X28), High Priority Industrial Wells (5W20), Cesspools (5W10), and any other type of Class V well that poses an immediate threat to underground sources of drinking water.

The table below breaks out the subcategories of Class V wells and lists the states where they can be found.

Class V well inventories in Region 5 are incomplete due to their vast number and due to shifting priorities and funding and staffing resources unique to each state.

Managing Shallow Disposal Systems in Region 5

EPA
Well
Code
Name of Well Type and Description Ground Water
Contamination
Potential
Potential Contaminants State Where Type is Known* to Exist
DRAINAGE WELLS (a.k.a. DRY WELLS)
5F1 Agricultural Drainage Wells - receive irrigation tailwaters, other field drainage, animal yard, feedlot, or dairy runoff, etc. High Pesticides, nutrients, pathogens, metals transported by sediments, salts. Illinois, Michigan, Minnesota
5D2 Storm Water Drainage Wells - receive storm water runoff frompaved areas, including parking lots, streets, residential subdivisions, building roofs, highways, etc. Moderate Heavy metals (Cu, Pb, Zn), organics, high levels of coliform bacteria. Contaminants from streets, roofs, landscaped areas. Herbicides, Pesticides. Illinois, Indiana, Michigan, Minnesota, Wisconsin
5D3 Improved Sinkholes - receive storm water runoff from developments located in karst topographic areas. High-Moderate Variable: pesticides, nutrients, coliform bacteria. Indiana, Minnesota, Ohio, Wisconsin
5D4 Industrial Drainage Wells wells located in industrial areas which primarily receive storm water runoff but are susceptible to spills, leaks or other chemical discharge High-Moderate Usually organic solvents, acids, pesticides, and various other industrial waste constituents. Similar to storm drainage wells but usually higher concentrations. Illinois, Indiana, Michigan, Minnesota, Wisconsin
5G30 Special Drainage Wells - used for disposing water from sources other than direct precipitation. Four types were reported: landslide control drainage wells, potable water tank overflow drainage wells (Idaho), swimming pool drainage wells (Florida) and lake level control drainage wells. Moderate-Low Chlorinated and treated water, pH imbalance, algicides, fungicides, muriatic acid. Illinois, Indiana, Michigan, Minnesota
GEOTHERMAL REINJECTION WELLS
5A5 Electric Power Reinjection Wells - reinject geothermal fluids used to generate electric power - deep wells. Moderate pH imbalance, minerals and metals in solution (As, B, Se), sulfates.  
5A6 Direct Heat Reinjection Wells - reinject geothermal fluids used to provide heat for large buildings or developments - deep wells. Moderate Hot geothermal brines with TDS between 2,000 to 325,000 mg/l. Co, CaSO4, Sr, Ba and As.  
5A7 Heat Pump/Air Conditioning Return Flow Wells - reinject groundwater used to heat or cool a building in a heat pump system - shallow wells. Low Potable water with temperatures ranging from 90° to 110° F, may have scale or corrosion inhibitors. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
5A8 Groundwater Aquaculture Return Flow Wells - reinject groundwater or geothermal fluids used to suport aquaculture. Non-geothermal aquaculture disposal wells are also included in this category. Moderate Used geothermal waters which may be highly mineralized & include traces of arsenic, boron, fluoride, dissolved & suspended solids, animal detritus, perished animals and bacteria. Michigan
DOMESTIC WASTERWATER DISPOSAL WELLS
5W9 Untreated Sewage Waste Disposal Wells - receive raw sewage wastes from pumping trucks or other vehicles which collect such wastes from single or multiple sources. (No treatment) High Soluble organic & inorganic compounds including household chemicals. Raw sewage with 99.9% water and 0.03% suspended solid. May contain pathogenic bacteria & viruses, nitrates, ammonia. Illinois
5W10 Cesspools - including multiple dwelling, community, or Regional cesspools, or other devices that receive wastes and which must have an open bottom and sometimes have perforated sides. Must serve greater than 20 persons per day if receiving solely sanitary wastes. (Settling of solids) High Soluble organic & inorganic compounds including household chemicals. Raw sewage with 99.9% water and 0.03% suspended solid. May contain pathogenic bacteria & viruses, nitrates, ammonia. Ohio
5W11 Septic Systems (Undifferentiated Disposal Method) - used to inject the waste or effluent from a multiple dwelling, business establishment, community or regional business establishment septic tank. Must serve greater than 20 persons per day if receiving solely sanitary wastes. (Primary Treatment) High-Low Varies with type of system: fluids typically 99.9% water (by weight) and 0.03% suspended solides: major constituents include nitrates, chlorides, sulfates, sodium, calcium, and fecal coliform. Illinois, Indiana, Michigan, Minnesota, Ohio
5W31 Septic Systems (Well Disposal Method) - examples of wells include actual wells, seepage pits, cavitettes, etc. The largest surface dimension is less than or equal to the depth dimension. Must serve greater than 20 persons per day if receiving solely sanitary wastes. (Less treatment for square area than 5W32) High-Low Varies with type of system: fluids typically 99.9% water (by weight) and 0.03% suspended solides: major constituents include nitrates, chlorides, sulfates, sodium, calcium, and fecal coliform. Illinois, Indiana, Michigan, Minnesota, Ohio
5W32 Septic Systems (Drainfield Disposal Method) - examples of drainfields include drain or tile lines, and trenches. Must serve more than 20 persons per day if receiving solely sanitary wastes. (More treatment per square area than 5W31) High-Low Varies with type of system: fluids typically 99.9% water (by weight) and 0.03% suspended solides: major constituents include nitrates, chlorides, sulfates, sodium, calcium, and fecal coliform. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
5W12 Domestic Wastewater Treatment Plant Effluent Disposal Wells - dispose of treated sewage or domestic effluent from small package plants up to large municipal treatment plants. (Secondary or further treatment) High-Low Lower levels of organics and bacteria than other septic systems and cesspools. Illinois, Indiana, Michigan, Minnesota, Wisconsin
MINERAL AND FOSSIL RECOVERY RELATED WELLS
5X13 Mining, Sand or Other Backfill Wells - used to inject a mixture of water and sand, mill tailings, and other solids into mined out portions of subsurface mines whether what is injected is a radioactive waste or not. Also includes special wells used to control mine fires and acid mine drainage wells. Moderate Acidic waters Illinois, Indiana, Ohio
5X14 Solution Mining Wells - used for in-situ solution mining in conventional mines, such as stopes leaching. Moderate-Low 2.4% sulfuric acid, pH less than 2 for copper & ferric cyanide solution for gold or silver.  
5X15 In-situ Fossil Fuel Recovery Wells - used for in-situ recovery of coal, lignite, oil shale, and tar sands. Moderate Steam, air, solvents, igniting agents.  
5X16 Spent-Brine Return Flow Wells - used to re-inject spent brine into the same formation from which it was withdrawn after extraction of halogens or their salts. Low Variable Michigan
INDUSTRIAL/COMMERCIAL/UTILITY DISPOSAL WELLS
5A19 Cooling Water Return Flow Wells - used to inject water which was used in a cooling process, both open and closed loop processes Low-Moderate Anti-sealing additives, thermal pollution, potential for industrial spills reaching ground water. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
5W20 Industrial Process Water and Water Disposal Wells - used to dispose of a wide variety of wastes and wastewaters from industrial, commercial, or utility processes. Industries include refineries, chemical plants, smetlers, pharmaceutical plants, laundromats an dry cleaners, tanneries, carwashes, laboratories, etc. Industry and waste stream must be specified (e.g., Petroleum Storage Facility - storage tank condensation water; Electric Power Generation Plant - mixed waste stream of laboratory drainage, fireside water, and boiler blowdown; Car Wash - Mixed waste stream of detergent, oil and grease, and paved area washdown; Electroplating Industry - spent solvent wastes, etc). High Potentially any fluid disposed by various industries, suspended solids, alkalinity, sulfate, volatile organic compounds. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
5X28 Automobile Service Station Disposal Well - repair bay drains connected to a disposal well. Suspected of disposal of dangerous or toxic wastes. Now regulated as a type of motor vehicle waste disposal well which includes disposal wells at all facilities that perform motor vehicle repair and maintenance (for boat, airplane, bus, tractor, etc.). High Heavy metals, solvents, cleaners, used oil and fluids, detergents, organic compounds. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
RECHARGE WELLS
5R21 Aquifer Recharge Wells - used to recharge depleted aquifers and may inject fluids from a variety of sources such as lakes, streams, domestic wastewater treatment plants, other aquifers, etc. High-Low Variable: water is generally of good quality Illinois, Indiana, Michigan, Minnesota, Wisconsin
5B22 Saline Water Intrusion Barrier Wells - used to inject water into fresh water aquifers to prevent intrusion of salt water into fresh water aquifers. Low Varies: advanced treated sewage, surface urban and agricultural runoff, and imported surface waters.  
5S23 Subsidence Control Wells - used to inject fluids into a non-oil or gas producing zone to reduce or eliminate subsidence associated with overdraft of fresh water and not used for the purpose of oil or natural gas production. Low No specific type of injected fluid noted, similar to aquifer recharge wells. Wisconsin
MISCELLANEOUS WELLS
5N24 Radioactive Waste Disposal Wells - all radioactive waste disposal wells other than Class IV wells. Unknown Low-level radioactive wastes. Illinois
5X25 Experimental Technology Wells - wells used in experimental or unproven technologies such as pilot scale in-situ solution mining wells in previously unmined areas. Low-Moderate Varies depending on project. Illinois
5X26 Aquifer Remediation Related Wells - wells used to prevent, control, or remediate aquifer pollution, including but not limited to Superfund sites. Unknown Nutrients used in Biodegredation of organics, oil/grease, phenols, toluene. Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
5X29 Abandoned Drinking Water Wells - used for disposal of waste. Moderate Potentially any kind of fluid, particularly brackish or saline water, hazardous chemicals and sewage. Indiana, Michigan, Minnesota
5X27 Other Wells - any other unspecified Class V wells: Well type/purpose and injected fluids must be specified. Unknown Variable Illinois, Indiana, Michigan, Minnesota, Ohio

*Note: "Known" indicates that the state UIC program has verified information for specific wells. State inventories for Class V wells are often incomplete due to lack of resources available for finding unknown wells. As such, any of the subcategories, while not listed on the inventory, may still exist.


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