In your community, there may be industrial

waste disposal wells, storm water drainage wells,

large-capacity septic systems,

and other Class V wells.

They are regulated and are

not allowed to endanger drinking water resources.

DRINKING

WATER

RESOURCES

DRINKING WATER

RESOURCES

OIL

SALT LAYER

BASE OF

UNDERGROUND

SOURCES OF

DRINKING WATER

BASE OF

UNDERGROUND

SOURCES OF

DRINKING WATER

BASE OF

UNDERGROUND

SOURCES OF

DRINKING WATER

HANCED

COVERY

OIL & GAS

RECOVERY

SALT

SOLUTION

MINING

SALT

MINING

URANIUM

SOLUTION

MINING

URANIUM

MINING

SCHOOL

STORM WATER

DRAINAGE

STREET

DRAINAGE

LIGHT

INDUSTRY APARTMENT

BUILDING

LARGE-CAPACITY

SEPTIC SYSTEMS

AUTOMOTIVE

SERVICE STATION

CONCENTRATED ANIMAL

FEEDING OPERATION

FARM HOUSE

LARGE-CAPACITY

CESSPOOL

FOOD

PROCESSING

DRINKING WATER PLANT

wells- 

and gas

n wastes

Class III wellsMinimize

environmental impacts

from solution mining

operations

Class V wellsManage the shallow injection

of all other fluids to prevent

contamination of drinking water resources

Class V wells continued

100 FEET 100 FEET

PRODUCTION WELL*

INDUSTRIAL

WASTE

AGRICULTURAL

DRAINAGE WELL

PUBLIC

WATER

SUPPLY

WELL

MOTOR VEHICLE

WASTE

DISPOSAL WELL

AUTOMOTIVE

SERVICE STATION

Class IV wellsPrevent ground water

contamination

by prohibiting

the shallow injection

of hazardous waste

except as part of

authorized

cleanup activities

Safe Drinking Water Act

Underground Injection Control (UIC) Program

Protecting Public Health and Drinking Water Resources

SOURCE WATER PROTECTION AREA

SHOPPING MALL

LIGHT INDUSTRY

WITH HOLDING TANKS

FOR OFF-SITE WASTE

DISPOSAL

AGRICULTURAL

ACTIVITIES

WITH BEST

MANAGEMENT

PRACTICES

WELLS ARE NOT

HE UIC PROGRAM

PRODUCTION WELL*

*PRODUCTION WELLS ARE NOT

REGULATED BY THE UIC PROGRAM

HAZARDOUS

WASTE

All large-capacity

cesspools are banned.

New motor vehicle waste

disposal wells are

banned nationwide.

Existing motor vehicle

waste disposal wells in

source water protection

areas or other sensitive

ground water areas must

close or receive a

permit.

water
Safe Drinking Water Act

Underground Injection

Control (UIC) Program

Protecting Public Health and Drinking

Water Resources

WHY DO WE HAVE A PROGRAM TO REGULATE

UNDERGROUND INJECTION?

Each year Americans generate large amounts of waste

fluids. More than 750 billion gallons of hazardous and nonhazardous fluids are disposed of safely through underground injection. The Underground Injection Control (UIC)

Program is designed to protect underground sources of

drinking water (USDWs) and provide a safe and costeffective means for industries, municipalities, and small

businesses to dispose of their wastewater, extract mineral

resources, and store water for the future. Illegal discharges

have the potential to contaminate our underground drinking

water resources. Preventing this contamination is vital

because most accessible fresh drinking water is found

underground in shallow formations called aquifers. Aquifers

provide water for more than 90 percent of the public water

systems in America. They also supply agricultural wells,

feed our lakes, and help recharge our streams and rivers,

particularly during dry periods. In addition, millions of

Americans living in rural areas rely on private wells that

draw their water from aquifers. Safe and clean drinking

water resources are essential for our growing population.

Protecting future drinking water resources is essential for

continued growth. The UIC Program prevents contaminants

from entering our drinking water resources to protect our

public health.

WHAT ARE INJECTION WELLS?

An injection well is any bored, drilled, or driven shaft, or dug

hole, whose depth is greater than its largest surface

dimension; an improved sinkhole; or a subsurface distribution system used to discharge fluids underground. These

wells range from deep, highly technical, and more frequently

monitored wells to shallow on-site drainage systems, such

as septic systems, cesspools, and storm water drainage

wells. There are five categories or “classes” of injection

wells based on function, construction, and operating

features.

WHAT IS THE STATUTORY BASIS FOR THE UIC

PROGRAM?

In 1974, Congress passed the Safe Drinking Water Act

(SDWA). Part of SDWA required the U.S. Environmental

Protection Agency (EPA) to report back to Congress on

waste disposal practices, and develop minimum federal

requirements for injection practices that protect public

health by preventing injection wells from contaminating

USDWs. USDWs are defined as aquifers or portions of

aquifers that have a sufficient quantity of ground water to

supply a public water system and contain fewer than 10,000

milligrams per liter (mg/l) or parts per million (ppm) total

dissolved solids (water that can be treated to drinking water

standards). This includes all current and future underground

drinking water resources.

HOW DOES THE UIC PROGRAM PROTECT PUBLIC HEALTH? WHO IMPLEMENTS THE UIC PROGRAM?

States and tribes may apply to EPA to obtain primary

enforcement responsibility, or primacy, to administer the UIC

Program. Primacy programs must meet the minimum

federal requirements, but may have more stringent requirements. Thirty-three states, Guam, the Commonwealth of the

Mariana Islands, and Puerto Rico have primacy for all

classes of injection wells. Seven states share primacy with

EPA. EPA directly implements the UIC programs for the

remaining states, the Virgin Islands, American Samoa, and

Indian Country.

WHAT CAN YOU DO TO PROTECT YOUR DRINKING

WATER?

Preventing contamination can save you money and protect

your family’s health. Here are some of the things you can do

to help protect your drinking water source:

■ Know where your drains go. Many homes or

businesses use septic systems or drywells for waste

disposal. These systems are designed for household

sanitary wastes only.

■ Become involved in Source Water Protection.

Every state is conducting Source Water Assessments

for its public water systems. These assessments will

identify the major potential sources of contamination

(including Class V wells) to public drinking water

supplies. The results will be provided to the public.

Communities will use this information to plan protection activities and identify Class V wells for proper

management to prevent contamination of drinking

water sources. The UIC Program has banned motor

vehicle waste disposal wells in source water protection areas. States are also encouraged to target these

areas for UIC protective measures.

■ Read your consumer confidence report. This

report, published once a year by the agency providing

you with your drinking water, gives you information

about the quality of your drinking water and information about your state’s source water assessment for

your system, when it has been completed.

FOR MORE INFORMATION:

Call the Safe Drinking Water Hotline (800) 426-4791 or the

Office of Ground Water and Drinking Water (202) 260-7077;

write to The UIC Program, Mail Code 4606, U.S. EPA, 1200

Pennsylvania Avenue, NW, Washington, D.C. 20460; or visit

the Web site at http://www.epa.gov/safewater/uic.html.

DEFINITIONS

IMPROVED SINKHOLE – A naturally occurring depression or other natural

crevice (for example, those found in limestone or volcanic rocks),

which has been modified for the purpose of directing and discharging

fluids underground.

SUBSURFACE DISTRIBUTION SYSTEM – An assemblage of perforated pipes,

drain tiles, or other similar mechanisms intended to distribute fluids

below the ground surface.

AUTHORIZATION BY RULE – An owner or operator of an injection well who

submits proper inventory information to the UIC regulatory authority

may construct or use his or her well as long as the injection activity

does not endanger USDWs.

NON-ENDANGERMENT – No owner or operator shall construct, operate,

maintain, convert, plug, abandon, or conduct any other injection activity in a manner that allows the movement of fluid containing any

contaminant into USDWs, if the presence of that contaminant may

cause a violation of any primary drinking water regulations or may

adversely affect the health of persons.

EPA established the UIC Program to set minimum federal requirements for all

injection wells that discharge hazardous and non-hazardous fluids above,

into, or below USDWs. They affect the siting, construction, operation, maintenance, monitoring, testing, and closure of injection wells. All operational

injection wells require authorization under general rules or specific permits.

Fluids cannot be injected if they may endanger a drinking water source.

■ Class I wells - Isolate hazardous, industrial and municipal wastes

through deep injection. Class I wells inject hazardous and nonhazardous wastes into deep, isolated rock formations below the

lowermost USDW. There are specific siting, construction, operating,

monitoring and testing, reporting and record keeping, permitting, and

closure requirements for all Class I wells. There are two main types of

Class I wells: hazardous waste wells and non-hazardous waste wells.

♦ Class I Hazardous Waste Disposal Wells are mainly used by

industries such as petroleum refining and metal, chemical, and

pharmaceutical production. These wells inject up to 2 miles below

the surface and are designed to prevent any waste from escaping

the injection zone. Because of the hazardous nature of the waste,

Class I hazardous well owners must also show that the hazardous

waste will not move from the injection zone for 10,000 years, or for

as long as the waste remains hazardous. Eighty-nine percent of all

hazardous waste disposal in the United States is done through Class

I wells. Class I hazardous waste wells are stringently regulated under

the SDWA (UIC Program) and the Resource, Conservation and

Recovery Act (RCRA). There are approximately 120 Class I hazardous wells in operation in the United States.

♦ Class I Non-Hazardous Waste Disposal Wells are used by industries

and municipal wastewater treatment facilities to dispose of nonhazardous waste, such as dilute manufacturing process waste and

treated sanitary wastewater. All Class I non-hazardous wells are

monitored, inspected, and tested regularly. There are approximately

380 Class I non-hazardous wells operating in the United States.

■ Class II wells - Inject oil and gas production wastes and materials.

Class II wells inject fluids associated with oil and natural gas production. Most of the injected fluid is brine pumped to the surface along with

oil and gas. This brine is often saltier than seawater and can contain

toxic metals and radioactive substances. By injecting the brine, Class II

wells prevent surface contamination of soil and water. In addition, well

operators inject residual brines, steam, polymers, and other fluids to

enhance the production of oil and gas. Class II well operators must

follow strict construction and conversion (from production wells)

requirements, except when historical practices in the state and geology

allow for different standards. Class II wells are permitted or authorized

by rule; the well owner or operator must meet all applicable requirements; and the wells are tested and inspected regularly. There are

about 147,000 Class II wells in operation in the United States.

■ Class III wells - Minimize environmental impacts from solution

mining operations. Class III wells inject fluids into rock formations to

dissolve and extract minerals. The injected fluids are pumped to the

surface and the minerals in solution are extracted. Generally, the fluid is

recycled into the same formation for further mineral extraction. More

than 50 percent of the salt and 80 percent of the uranium extraction in

the United States involves Class III injection wells. These wells are

permitted or authorized by rule. Class III well owners or operators must

case and cement their wells, and the wells must be tested regularly.

There are about 190 mining sites with approximately 17,000 Class III

wells operating in the United States.

■ Class IV wells - Prevent ground water contamination by prohibiting

the shallow injection of hazardous waste except as part of authorized cleanup activities. Class IV wells were shallow wells used to

inject hazardous or radioactive wastes. They are banned except when

operated to inject treated contaminated ground water back into the

original aquifer. These wells can be operated only with federal or state

approval under the RCRA or Superfund programs. There are about 40

waste cleanup sites with Class IV wells in operation in the U.S.

■ Class V wells - Manage the shallow injection of all other fluids.

Class V wells are injection wells that are not included in Classes I

through IV. Class V wells inject non-hazardous fluids into or above an

aquifer. They are typically shallow, on-site disposal systems, such as

floor and sink drains that discharge into dry wells, septic systems, leach

fields, and similar types of drainage wells, although there are some

Class V wells that are deep injection wells. When properly designed,

sited, operated, and maintained, Class V wells do not endanger drinking

water sources. Most Class V wells are authorized by rule. An estimated

500,000 to 685,000 Class V wells are in operation in the United States.

Examples of Class V wells include the following:

♦ Agricultural Drainage Wells are used to drain farmland for cultivation.

They include improved sinkholes, abandoned drinking water wells,

and underground drain tiles and cisterns.

♦ Industrial Waste Disposal Wells are used to dispose of non-hazardous industrial or commercial waste and fluids. These wastes and

fluids include wastewater from a wide variety of industries including

petroleum refineries, carwashes, laundromats, commercial printers,

food processors, chemical manufacturers, electroplaters, small

machinery, tool and die, and other industrial operations.

♦ Large-Capacity Cesspools are typically drywells that receive untreated sanitary waste and which have an open bottom and, sometimes, perforated sides. Large-capacity cesspools are used by

multiple dwelling units, business establishments, community or

regional establishments such as churches and shopping malls, and

other facilities such as camp grounds and highway rest stops. New

large-capacity cesspools are banned and existing large-capacity

cesspools must close.

♦ Large-Capacity Septic Systems are on-site systems that partially

treat and dispose of sanitary wastewater. Most large-capacity septic

systems consist of a septic tank and a leach field. Large-capacity

septic systems are used by multiple dwelling units, business establishments, community or regional establishments, and other facilities.

♦ Motor Vehicle Waste Disposal Wells are used to dispose of fluids

from the repair or maintenance of motor vehicles. Fluids entering

these wells include organic chemicals such as petroleum products

and inorganic chemicals such as heavy metals. New motor vehicle

waste disposal wells are banned and existing wells must close or

receive a permit.

♦ Saline Intrusion Barrier Wells (not shown) are used to inject water

into an aquifer to prevent intrusion of salt water into that aquifer.

♦ Storm Water Drainage Wells are used to remove storm water and

urban runoff from surfaces such as roadways, roofs, and paved

surfaces to prevent flooding.

♦ Subsidence Control Wells (not shown) are used to control land

sinking, or subsidence, caused by ground water withdrawal.

NOTE: The UIC Program does not regulate sanitary discharges from

individual residential septic systems and cesspools, and nonresidential septic systems and cesspools that inject only sanitary waste and

have the capacity to serve fewer than 20 persons per day.

There are many other subcategories of Class V wells. Additional information

can be found by visiting EPA’s UIC Program Web site at http://www.epa.gov/

safewater/uic.html.