United States
Environmental Protection

Agency
      Office of Water
      (4606)

      Washington, DC 20460
EPA816-H-01-003

August 2001

www.epa.gov/safewater
Safe   Drinking   Water   Act
Underground Injection  Control  (UIC)  Program
Protecting Public  Health  and Drinking  Water  Resources
    Class I wells-
   Isolate hazardous,
 industrial and municipal
   wastes through
    deep injection
CHEMICAL
 I PLANT
                        Class II wells-
                      Inject oil and gas
                      production wastes
                                Class III wells-
                                  Minimize
                             environmental impacts
                              from solution mining
                                 operations
        rf^WASTE WATER
         TREATMENT PLANT
             «--
            •• r	
  TREATED

WASTE WATER
WAbTE WATEK
                   DRINKING WATER
                     RESOURCES
                      BASE OF
                   UNDERGROUND
                    SOURCES OF
                     .NKING WATER
                     CONFINING
                     FORMATIO
                     CONFINING
                     :ORMAT|ON
                     CONFINING
                     iFORMATIOH
       HAZARDOUS
    AND NON-HAZARDOUS
    INDUSTRIAL WASTES
                     CONFINING
                     IFORMATIO
                     CONFINING
                     FORMATIO
                                         BASE OF
                                       UNDERGROUND
                                        SOURCES OF
                                      DRINKING WATER
                                                            '  i '    SALT LAYER
                                                        ^K     t

                                                         'PRODUCTION WELLS ARE NOT
                                                        REGULATED BY THE UIC PROGRAM
                                                   Class IV wells-
                                                 Prevent ground water
                                                   contamination
                                                   by prohibiting
                                                 the shallow injection
                                                 of hazardous waste
                                                  except as part of
                                                     authorized
                                                  cleanup activities
                                      J
                             'PRODUCTION WELLS ARE NOT
                            REGULATED BY THE UIC PROGRAM
                                                                                                   APARTMENT*.
                                                                                                    BUILDING*
                                                                            AUTOMOTIVE -
                                                                          SERVICE STATION
                                                                                                                                         INDUSTRIAL  .
                                                                                                                                          WASTE
                                                                                                                          STORM WATER
                                                                                                                           DRAINAGE
                                                                                         LARGE-CAPACITY
                                                                                         SEPTIC SYSTEMS
                                                                                     DRINKING
                                                                                      WATER
                                                                                    RESOURCES
                                                                                                                        BASE OF
                                                                                                                      UNDERGROUND
                                                                                                                      SOURCES OF
                                                                                                                       NKING WATER
                                                                                                               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.
                                                                                                                      Class V wells continued
                                                                                              LIGHT INDUSTRY
                                                                                             WITH HOLDING TANKS
                                                                                             FOR OFF-SITE WASTE
                                                                                                DISPOSAL
                                                                                                                   DRINKING WATER PLANT
                                                                                                                                                        LARGE-CAPACITY
                                                                                                                                                          CESSPOOL
                                                                                                                 PUBLIC
                                                                                                                 WATER
                                                                                                                 SUPPLY
                                                                                                                 WELL
                                                                                       AGRICULTURAL
                                                                                       DRAINAGE WELL
                                                                                                  DRINKING WATER
                                                                                                   RESOURCES
                                                                                            BASE OF
                                                                                          UNDERGROUND
                                                                                           SOURCES OF
                                                                                          DRINKING WATER
                                                                                                                                       MOTOR VEHICLE
                                                                                                                                         WASTE
                                                                                                                                       DISPOSAL WELL
                                                                                                                                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.

-------
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 non-
hazardous fluids are disposed of safely through under-
ground injection. The Underground Injection Control (UIC)
Program  is designed to protect underground sources of
drinking water (USDWs) and provide a safe and  cost-
effective  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 distribu-
tion 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?

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,  mainte-
nance, 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.



    I Class I wells - Isolate hazardous, industrial and municipal wastes
     through deep injection. Class I wells inject hazardous and non-
     hazardous 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.

     4 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  hazard-
        ous wells in operation in the  United States.

     4 Class I Non-Hazardous Waste Disposal Wells are used by industries
        and municipal wastewater treatment facilities to dispose of non-
        hazardous 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.

    I Class II wells - Inject oil and gas production wastes and materials.
     Class II wells inject  fluids associated with  oil and natural gas produc-
     tion. 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 require-
     ments; and the wells are tested and inspected regularly.  There are
     about 147,000 Class II wells in operation in the United States.

    I 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.

    I Class IV wells - Prevent ground water contamination by prohibiting
     the shallow injection of hazardous waste except as part of autho-
     rized 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:

     4 Agricultural  Drainage  Wells are used to drain farmland for cultivation.
        They include improved sinkholes, abandoned drinking water wells,
        and underground drain tiles and cisterns.

     4 Industrial Waste Disposal Wells are used to dispose of non-hazard-
        ous 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.

     4 Large-Capacity Cesspools  are typically drywells that receive un-
        treated sanitary waste and  which have an open bottom and, some-
        times, 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.

     4 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 estab-
        lishments, community or regional establishments,  and other facilities.

     4 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.

     4 Saline Intrusion Barrier Wells (not shown) are used to  inject water
        into an aquifer to prevent intrusion  of salt water into that aquifer.

     4 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.

     4 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 nonresiden-
        tial 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.
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 require-
ments. 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 protec-
     tion 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 protec-
     tion 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 informa-
     tion 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  ac-
tivity 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.


-------