Underground Injection Control Program

Class I and V Well Inventory (Excel spreadsheet, as of April 15, 2014) 

Examples of different classifications of wellsThe Underground Injection Control (UIC) program is responsible for the regulation of Class I, IV and V injection wells, and for assuring that their operation does not contaminate underground sources of drinking water. The UIC program was established under the authority of Ohio Revised Code sections 6111.043 and 6111.044, and regulates Class I, IV, and V wells by implementing Chapter 3745-34 of the Ohio Administrative Code.

Please consult the U.S. EPA web site for a complete description of the various classes of injection wells as well as a detailed overview of the U.S. EPA's UIC program

Class I Injection Wells

Class I injection well diagramWhat is a Class I Injection Well?

Class I wells inject hazardous and non-hazardous wastes into deep, isolated rock formations that are thousands of feet below the lowermost underground source of drinking water.

Class I injection wells inject far below the lowermost aquifer. Injection zones typically range from 1,700 to more than 10,000 feet in depth. The injection zone is separated from any aquifers by an impermeable “cap” rock called the confining layer, along with additional layers of permeable and impermeable rock and sediment. 

Class I Wells in Ohio

Three facilities in Ohio currently operate a total of ten Class I injection wells regulated by Ohio EPA. Vickery Environmental (4 wells) operates a commercial waste disposal facility, receiving many types of waste from multiple sources. Innovene USA (4 wells) and AK Steel (2 wells) dispose of wastes generated on site during normal manufacturing operations. Fact sheets are available for the three active Ohio Class I injection well facilities:

Well Siting and Construction

Owners and Operators of Class I injection wells are required to apply to Ohio EPA for a permit for each well:

Permits are granted only after extensive data review followed by issuance of draft permits open to public comment.

All Class I wells have strict siting, construction, operation and maintenance requirements designed to ensure protection of the uppermost sources of drinking water (USDWs). Wells injecting hazardous wastes have siting requirements to show that, with a reasonable degree of certainty, there will be no migration of hazardous constituents from the injection interval. 

Class I Injection Wells - Frequently Asked Questions


Wastes are generated from a variety of sources ranging from steel mill operations to plastics production to manufacturing of agricultural chemicals. Some wastes are a product of other waste disposal methods (landfill leachate) or anti-pollution devices (wastewater generated by air pollution control equipment).
Recycling of wastes, while on the rise throughout industry, is not always the most cost-effective means for businesses to manage waste waters. Further, some wastes are difficult to reclaim or technology simply does not yet exist to recycle the material. Another option available to industry is to reduce the amount of wastes generated.

For facilities operating a Class I injection well, pollution prevention is a required component of facility operations. Each facility is required per section 6111.045 of the Ohio Revised Code to prepare and adopt a pollution prevention plan to identify technically and economically feasible measures that will be taken to reduce the amount of wastes generated at the facility. The facilities pollution prevention plan must be updated every three years.
class 1 wellWastes placed in the injection interval displace the salty ground water or brines naturally contained in the pores of the rock formations near the wellbore. With continued injection, the brines are pushed farther from the well by the enlarging plume of wastes which is roughly cylindrical in shape. As a simplified example, an injection interval one hundred feet thick and containing ten percent pore spaces, would accept nearly 60 million gallons within a five hundred foot radius of the well.
Class I wells are sited only in areas where the injection interval and confining zone are very extensive laterally. Thus, if injection of fluids does not create substantial increases in formation pressure which cause the injection pressure limitations to be approached, many wells (or injection interval) have nearly unlimited capacity. However, Class I hazardous wells do have volume limitations placed on them based on computer modeling performed during the No-Migration demonstration.
With injection over many years, a slow buildup of pressure usually occurs in the injection interval (i.e., the rock layer into which the waste is injected). Pressures are highest near the well and decline rapidly at increasing distances from the well. However, because the injection interval is so extensive, injected fluids can continuously flow away from the well, thus preventing a great buildup of pressure near the well. For this reason, when injection ceases, pressures in the injection interval slowly return to near original pressures further demonstrating the rock formation's ability to accept the injected fluids. Additionally, injection pressure limitations prevent injection at pressures which could cause fractures in the injection or confining zones.
class 1 wellInformation reviewed in as part of the permitting process and in demonstrations allows a determination, with reasonable certainty that injected fluids will remain in the permitted intervals. Additionally, periodic testing is required to be performed by operators to ensure that there is no movement of fluids into a USDW. These procedures are witnessed by Ohio EPA and results of all tests are subject to Ohio EPA's review and approval.

There are numerous tests to determine fluid movements; one test uses a temperature sensor run through the length of the well to identify zones which have accepted fluid. Testing with an advanced microphone system allows recognition of flow behind cemented casing. Annual pressure fall-off testing provides information on the condition of the injection interval including the presence or absence of fractures. Finally, ground water monitoring is also conducted at facilities. Monitoring wells are used to observe ground water quality in the lowermost USDW or to monitor pressure and chemistry in deeper zones above the injection interval.

Each facility is required to conduct routine sampling and chemical analysis of their injectate and to report the results to Ohio EPA. The agency also conducts additional sampling on a limited basis.

Class IV Injection Wells

class IV injection wellWhat is a Class IV Injection Well?

Class IV wells are defined in Ohio Administrative Code (OAC) Rule 3745-34-04(D). Class IV wells are shallow wells used to inject hazardous or radioactive wastes into or above a geologic formation that contains an underground source of drinking water. In 1984, U.S. EPA banned the use of Class IV injection wells for disposal of hazardous or radioactive waste. Now, these wells may only be operated as part of a U.S. EPA- or state-authorized ground water clean-up action. There are about 32 waste clean-up sites with Class IV wells in the United States.

What is the difference between Class IV and Class V injection wells? 

In general, both shallow Class IV and Class V wells inject fluids into or above the uppermost underground source of drinking water and may be of similar construction. The difference between Class IV and Class V wells is the quality of the fluid being injected. Class V wells may only inject non-hazardous fluids that will not endanger underground sources of drinking water. However, if a Class V well is misused and receives hazardous waste, as defined by the Resource Conservation and Recovery Act, the well would be considered a Class IV well and therefore be banned.

Class IV wells are prohibited by OAC Rule 3745-34-08 unless the injection wells are used to inject contaminated ground water that has been treated and is being injected into the same formation from which it was drawn. These remediation injection wells are authorized by rule for the life of the well if such subsurface emplacement of fluids is approved by the director of Ohio EPA and/or U.S. EPA as part of a remediation program pursuant to provisions for cleanup of releases under Chapter 3734 of the Revised Code and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, 42 U.S.C. 9601-9675, or pursuant to requirements and provisions under the Resource Conservation and Recovery Act, 42 U.S.C. 6901-6992k..

When an unauthorized Class IV well is discovered, the UIC Program coordinates with the Division of Materials and Waste Management to ensure that they are plugged appropriately and that any necessary corrective actions are taken at the site. All Class IV wells must submit information to the Underground Injection Control program per OAC Rule 3745-34-11(L). In addition, all unauthorized Class IV wells must be closed per the requirements of OAC Rule 3745-34-08(B) which includes submitting a closure plan at least 30 days prior to closure and disposing of all waste materials per all applicable laws and regulations.

Class V Injection Wells

class 5 well schematic

What is a Class V Injection Well?

Class V wells are used to inject non-hazardous fluids underground. Fluids are injected either into or above an underground source of drinking water. There are 17 different types of Class V wells. Examples of Class V wells include, among others, surface water runoff drainage wells, septic systems, dry wells, motor vehicle waste disposal wells, and industrial, commercial, and utility disposal wells.

Most Class V wells are "low-tech" and depend on gravity to drain fluids directly below the land surface. Drywells, cesspools, and septic system leach fields are examples of simple Class V wells. Because their construction often provides little or no pretreatment and these fluids are injected directly into or above an underground source of drinking water, proper management is important.

More sophisticated Class V wells may rely on gravity or use pressure systems for fluid injection. Some sophisticated systems include advanced wastewater disposal systems used by industry, experimental wells used to test new or unproven technologies, and even systems used to inject and store water for later reuse.

The owner or operator of a Class V well is required by OAC Rule 3745-34-11(M) to notify Ohio EPA of the well's existence. The notification is required to be submitted within 30 days of installing a new well and shall include a completed "Underground Injection Control Class V Well Inventory Form" if an inventory form has not already been submitted. 

Owners or operators of Class V wells associated with golf course maintenance facilities should also reference the following fact sheet:

Class V Injection Wells - Frequently Asked Questions


All Class V wells are required to be registered by the owner or operator of the well with the Ohio EPA (OAC Rule 3745-34-11(M)). Registration is done by submitting a completed inventory form to Ohio EPA. No Class V injection well is authorized to operate unless an inventory form has been completed and submitted to Ohio EPA.

class 5 wellAll Class V injection wells injecting industrial waste or other waste (as defined by OAC Rule 3745-34-01) must possess a permit to drill and a permit to operate prior to injection beginning (OAC Rule 3745-34-11(A)). All Class V injection wells injecting only sanitary waste (as defined by OAC Rule 3745-34-01) that have been permitted or authorized by Ohio EPA’s Division of Surface Water or the relevant local health department are authorized by rule provided a complete inventory form has been submitted to the UIC program (OAC Rule 3745-34-11(D)). All other types of Class V injections wells (such as storm water drainage wells) are authorized by rule to inject wastes into the subsurface provided they have been registered with Ohio EPA (OAC Rule 3745-34-11(I)).

The Director may require any Class V well authorized by rule to apply for and obtain a UIC permit if the injection well is not in compliance with any requirements of OAC Chapter 3745-34 or, if the protection of a underground source of drinking water necessitates that injection be regulated by requirements not contained in these rules (OAC Rule 3745-34-11(L)).
Class V injection wellOAC Rule 3745-34-12 and OAC Rule 3745-34-16 lists the requirements for submitting a permit to drill and a permit to operate to the Ohio EPA for a Class V injection well. OAC Rule 3745-34-26 and OAC Rule 3745-34-27 also contain requirements concerning a permit application. The following application forms for various types of Class V wells are available by clicking the links below or by contacting Valerie Orr via telephone (614) 644-2752 or email:

Yes, under certain conditions, soil and ground water remediation efforts may warrant the subsurface injection of fluids. If the remediation well is needed as part of a clean up effort approved by U.S. EPA or Ohio EPA under RCRA Subtitle C or CERCLA, then the well is approved by rule as long as inventory information is submitted (OAC Rule 3745-34-08(C)). Operators of Class V Aquifer Remediation wells where fluids to be injected do not exceed primary drinking water regulations, MCLs or health advisory limits must comply with OAC Rule 3745-34-11(H) to avoid having to submit a permit application.
Each application for a Class V permit to drill and install must be accompanied by a non-refundable fee of $2000 dollars for each application.

Each application for a Class V permit to operate must be accompanied by a non-refundable fee of $2000 dollars for each application. This permit must be renewed at least every five years.

motor vehicle disposal well schematicYes! All motor vehicle waste disposal wells and all large capacity cesspools are illegal under both federal and Ohio regulations (OAC Rules 3745-34-11(B) and (C)). Large capacity cesspools are considered injection wells used to dispose of untreated sanitary waste (OAC Rule 3745-34-01). Motor vehicle waste disposal wells are wells that are used to dispose of fluids from the repair of motor vehicles including cars, trucks, buses, vans, motorcycles, airplanes, farm equipment, constructions equipment and other types of motorized vehicles (OAC Rule 3745-34-01).

class 5 wellClosure requirements are specified in OAC Rule 3745-34-11(O). All types of Class V injection wells must be closed in a manner that is protective of human health and all waste materials removed from the wells must be disposed of in accordance with all applicable laws and regulations (OAC Rule 3745-34-7(A)). Owners or operators for all types of Class V injection wells must notify the Ohio EPA of the intent to close a Class V injection well at least 30 days prior to closure of the well. The owners or operators of Class V injection wells used to dispose of industrial or other wastes must submit a closure plan detailing, at a minimum, the inventory information concerning the well, procedures for removing any sludges or wastes from the well, and procedures for plugging the well.

Underground Injection Control Contacts