United States
Environmental Protection
Agency
Region. 5
Office of Public Affairs
230 South Dearborn Street
Chicago; Illinois 60604
Illinois, Indiana,
Michigan, Minnesota,
Ohio, Wisconsin
vxEPA
FACT
SHEET
Class V Injection Well Closure
July 1991
WHAT ARE INJECTION WELLS AND
WHY ARE THEY A PROBLEM?
Underground injection wells are not like the wells we get drinking water from.
They have a fundamental difference: Instead of removing fresh water from the ground,
these wells insert waste liquids. Properly done, this is a safe way to dispose of wastes.
The problem is that it isn't always done properly, and then the ground water that we
drink can become polluted.
Ground water is an essential part of our water supply (see Box 1); we need it
for our health, recreation, economic growth, and agricultural production—the quality
of life we all share. Contamination is a grave threat, though. Once it has been
contaminated, ground water can be very difficult, if not
impossible, to clean.
Unlike surface water, ground water does not flow
in a series of lakes and rivers. Ground water is stored
beneath our communities in formations of rock, sand,
gravel, and soil. Precipitation seeps into the ground and
fills the pores of rock formations, similar to the way water
fills a sponge. Unfortunately, this "rock sponge" absorbs
more than water—things such as benzene, toluene, methy-
lene chloride, tetrachloroethylene (PCE), trichloroethylene
Box 1. Our dependence on ground water
(TCE), and other chemicals—all common industrial wastes, many of which can cause
cancer, birth defects, developmental problems, and other health problems.
To protect ground water from contamination, Congress has established the
Underground Injection Control (UIC) program. This program sets rules for the
operation and construction of injection wells and organizes them into five classes (see
Box 2).
The subject of this fact sheet is Class V wells, the most common, and one of
the most environmentally dangerous types of injection well. Unlike other classes of
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Box 2. Classes of injection wells
injection wells that are often thousands of feet deep, most
of these wells are only a few feet deep. In fact, a well is
technically any hole that is deeper than it is wide. This
means that the hole in a backyard that an unthinking person
might pour used motor oil into is an underground injection
well. In fact, most Class V wells are not much more
sophisticated than a simple hole in the ground that wastes
are poured into.
Shallow injection wells can be especially dangerous
if they are near drinking water sources. Injection wells
should not be in vulnerable ground water areas because of
the potential for contaminating nearby drinking-water
wells.
WHO USES THESE WELLS?
Shallow injection wells fall into two main catego-
ries: drainage wells and disposal wells. Over 80 percent
of all Class V injection wells are in these two groups (see
the attached table for a detailed list of Class V well types).
The other 20 percent of shallow injection wells
include such diverse groups as geothermal reinjection wells
that use the temperature of the Earth's core to heat build-
ings, radioactive waste disposal wells that dispose of low-level radioactive wastes, and
even abandoned drinking-water wells that are used for waste disposal.
Drainage wells are used for removing water from places that have too much of
it. Farmers use them to keep their fields dry, and cities use them to keep their streets
dry. Often city storm sewers use injection wells to dispose of stormwater runoff. This
is not just rainwater, though. It can become contaminated with fertilizers, animal
wastes, heavy metals, and other pollutants. Once the contaminated water enters the
well, the ground water can become contaminated also.
Disposal wells are the type of injection well most often used by businesses (see
Box 3). Most of these wells are little more than a drain in the floor that leads to a
Class I Deep welts used to inject
hazardous wastes or dispose
of nonhazardous industrial
waste and treated municipal
sewage below the deepest
underground source of drink-
ing water.
Class II Wells used to inject fluids
associated with the produc-
tion of oil and natural gas, or
fluids and compounds used
lot enhanced hydrocarbon
recovery,
Class III Wells that Inject fluids used in
the subsurface mining of
minerals.
Class IV Wells that dispose of hazard-
ous or radioactive wastes into
or above an underground
source of drinking water.
(These wells are banned and
must be plugged.)
Class V Wells, not included in the
other classes, that inject non-
hazardous fluid into or above
an underground source of
drinking water. These wells
are commonly referred to as
shallow injection welts.
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Laundromats
Phbtdflraphic labdratdries
Box 3. Businesses that use disposal wells
septic tank or dry well. The problem is that these septic
;;;f^iliiiiiti6^:'::^:^' ••:' ':::^-:--:-:-:^:^:^::
systems drain into the ground water. Septic tanks and dry
wells do a fairly good job of treating normal domestic
wastes, but they can't handle industrial chemicals. If the
chemicals are toxic when they enter the septic tank, they're
just as toxic when they enter the ground water.
Automotive service stations frequently damage
ground water supplies with Class V wells. Waste oil,
transmission fluid, battery acid, degreaser—it all goes down
the drain and into the water. These liquids may be harmless when they're in your car,
but not when they're in your coffee.
Another business problem can be laundromats. These businesses sometimes
discharge water high in detergents and other laundry chemicals into their septic systems,
which then contaminate ground water. Even photographic darkrooms sometimes put
the ground water at risk. The developers and fixers—chemicals used to develop
film—are usually just poured down the sink, which empties in the septic tank, which
drains into ground water.
WHAT IS THE EPA DOING?
Operators of Class V injection wells were required to submit information about
their wells by June 25, 1985—very few did so, and those that did not lost the right to
continue using their wells. It is illegal to operate an underground injection well without
a permit from EPA.
In 1987, the Region 5 Underground Injection Control section started a project
to collect inventory information on Class V injection wells in Indiana, Michigan, and
Minnesota. (The other Region 5 States—Illinois, Wisconsin, and Ohio—have their own
underground injection control programs.) Through this effort, more than 2,300
injection wells were identified in Indiana, Michigan, and Minnesota. This is by no
means a comprehensive inventory; EPA believes that many more wells exist, but they
haven't been identified yet. In an effort to identify all these wells, EPA is beginning
to organize volunteer groups to search communities for injection wells.
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Although there are 32 types of Class V wells, EPA has determined that types
5X28 (Automobile Service Station Related Waste Disposal) and 5W20 (Industrial
Process Waste Water Disposal) pose the greatest threat to the environment. Identified
operators of these wells were told to cease injection and submit either permit applica-
tions for continued operation or plans for the permanent closure of the well. Also,
operators were told to submit data so EPA could determine if injected fluids had already
contaminated the ground water.
In 1990, EPA sent closure letters to operators of 48 Class V wells. By
December 31, 1991, all these wells are scheduled to be closed. This year, Region 5
sent closure letters to operators of 200 Class V wells. Many offenders have not been
identified by the EPA; so, persons knowing of Class V injection well operators are
encouraged to relay that information to the EPA.
WHAT CAN OPERATORS DO?
EPA gives operators of Class V injection wells two options: They can close the
well permanently, or they can apply for a permit for its continued operation.
Closing the well does not necessarily mean removing the septic tank or tearing
the sink off the wall. It means taking measures to prevent nondomestic wastes from
entering the septic tank. An easy way to do this is to install a holding tank that gets
periodically emptied by a waste hauler. For example, a service station could reroute
its floor drain from the septic tank to a holding tank. The motor oil and other chemicals
would flow into the holding tank, but the domestic wastes would continue to enter the
septic system.
Another way to close the well is to connect it to a municipal waste treatment
system. In this way, the wastes could be properly treated and would not be able to
enter the ground water.
The operator's second choice is to obtain a permit from the EPA. This is more
than just sending in a form. The operator must be able to prove that continued
operation of the well does not pose a threat to ground water. EPA will provide
information on the permitting process to interested parties. (See phone numbers at end.)
There are some treatment processes that would allow the continued operation
of the wells, but most oil/water separators are not acceptable. These separators are not
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designed to protect the environment, but instead to keep waste oil from clogging the
septic system. These devices do not remove all the oil and they remove none of the
antifreeze and other chemicals in the waste water.
WHO HAS MORE INFORMATION?
If you want additional information on Class V injection wells, contact either of
the EPA offices listed below:
U.S. Environmental Protection Agency Region 5
Underground Injection Control Section (5WD-TUB-9)
230 South Dearborn St.
Chicago, IL 60604
Phone: (312) 886-4298
U.S. Environmental Protection Agency Region 5
Office of Public Affairs (5PA-14)
230 South Dearborn St.
Chicago, IL 60604
Phone: (800) 572-2515 (in Illinois)
(800) 621-8431 (outside Illinois)
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Class V Injection Well Subclasses
Name of Well Type and Description
DRAINAGE WELLS (a.k.a. DRY WELLS)
Agricultural Drainage Wells — receive irrigation tailwaters, other field
drainage, animal yard, feedlot, or dairy runoff, etc.
Storm Water Drainage Wells — receive storm water runoff from paved
areas, including parking lots, streets, residential subdivisions, building
roofs, highways, etc.
Improved Sinkholes — receive storm water runoff from developments
located in karst topographic areas.
Industrial Drainage Wells — wells located in industrial areas which
primarily receive storm water runoff but are susceptible to spills, leaks,
or other chemical discharge.
Special Drainage Wells — used for disposing water from sources other
than direct precipitation. Four types were reported: landslide control
drainage wells (Montana), potable water lank overflow drainage wells
(Idaho), swimming pool drainage wells (Florida), and lake level control
drainage wells (Florida)
GEOTHERMAL REINJECTION WELLS
Electric Power Reinjection Well: — reinject geothermal fluids used to
generate electric power — deep wells.
Direct Heat Reinjection Wells — reinject geothermal fluids used to
provide heat for large buildings or developments — deep wells.
Heat Pump/ Air Conditioning Return Row Wells — reinject groundwater
used to heat or cool a building in a heal pump system — shallow wells.
Groundwater Aquaculture Return Flow Wells — reinject groundwater
or geothermal fluids used to support aquaculture. Non-geothermal
aquaculture disposal wells are also included in this category (e.g. Marine
aquariums in Hawaii use relatively cool sea water).
DOMESTIC WASTEWATER DISPOSAL WELLS
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)
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)
Septic Systems (Undifferentiated Disposal Method) — used to inject the
waste or effluent from a multiple dwelling, business establishment, com-
munity, or regional business establishment septic tank. Must serve
greater than 20 persons per day if receiving solely sanitary wastes.
(Primary Treatment)
Septic Systems (Well Disposal Method) — examples of wells include
actual wells, seepage pits, cavitettes, etc. The largest surface dimen-
sion is less than or equal to the depth dimension. Must serve greater
than 20 pesons per day if receiving solely sanitary wastes. (Less treat-
ment per square area than 5W32)
Septic System (Drainfield Disposal Method) — examples of drainfields
include drain or tile lines, and trenches. Must serve more than 20 per-
sons per day if receiving solely sanitary wastes. (More treatment per
square area than 5W31)
Domestic Wastewater Treatment Plant Effluent Disposal Wells — dispose
of treated sewage or domestic effluent from small package plants up
o large municipal treatment plants. (Secondary or further treatment)
MINERAL AND FOSSIL FUEL RECOVERY RELATED WELLS
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.
Solution Mining Wells — used for in-situ solution mining in conven-
tional mines, such as slopes leaching.
n-situ Fossil Fuel Recovery Wells — used for in-situ reco%xry of coal.
ignite, oil shale, and tar sands.
Spent-Brine Return Flow Wells — used to reinject spent brine into the
same formation from which it was withdrawn after extraction of
lalogcns or their salts.
Ground Water
Contamination
Potential
High
Moderate
High-Moderate
High-Moderate
Moderate-Low
Moderate
Moderate
Low
Moderate
High
High
High-Low
High-Low
High-Low
High-Low
Moderate
Moderate-Low
Moderate
Low
Potential Contaminants
Pesticides, nutrients, pathogens, metals transported b)
sediments, salts.
Heavy metals (Cu. Pb, Zn) organics. high levels of coliform
bacteria. Contaminants from streets, roofs, landscaped areas.
Herbicides, Pesticides.
Variable: pesticides, nutrients, coliform bacteria.
Usually organic solvents, acids, pesiicides, and various other
industrial waste constituents. Similar to storm drainage wells
but usually higher concentrations.
Chlorinated and treated water, pH imbalance, algaecides,
fungicides, muriatic acid.
pH imbalance, minerals and metals in solution. (As, Bo, Se),
sulfates.
Hot geothermal brines with TDS between 2,000 to 325,000
mg/1. Co,, CaSO,, Sr and Ba, As.
Potable water with temperatures ranging from 90° to 110"
F., may have scale or corrosion inhibitors.
Used geothermal waters which may be highly mineralized &
include traces of arsenic, boron, fluoride, dissolved &
suspended solids, animal detritus, perished animals and
bacteria.
Soluble organic & inorganic compounds including household
chemicals. Raw sewage with 99.9% water and .03% sus-
pended solid. May contain pathogenic bacteria & viruses.
nitrates, ammonia.
Soluble organic & inorganic compounds including household
chemicals. Raw sewage with 99.9% water and .03% sus-
pended solid. May contain pathogenic bacteria & viruses,
nitrates, ammonia.
Varies with type of system: fluids typically 99.9% water (by
weight) and .03% suspended solids: major constituents in-
clude nitrates, chlorides, sulfates, sodium, calcium, and fecal
coliform.
Varies with type of system: fluids typically 99.9% water (by
weight) and .03% suspended solids: major constituents in-
clude nitrates, chlorides, sulfates, sodium, calcium, and fecal
coliform.
Varies with type of system: fluids typically 99.9% water (by
weight) and .03% suspended solids: major constituents in-
clude nitrates, chlorides, sulfates, sodium, calcium, and fecal
coliform.
Lower levels of organics and bacteria than other septic
systems and cesspools.
Acidic waters
t
2.4% sulfuric acid. pH less than 2 for copper & ferric cyanide
solution for gold or silver.
Steam, air, solvents, igniting agents.
Variable
EPA
Well
Code
5F1
5D2
5D3
5D4
5G30
5A5
5A6
5A7
5A8
5W9
5W10
5WII
5W3I
5W32
5W12
5X13
5X14
5X15
5X16
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(continued)
Name of Well Type and Description
IrVDL'STRIAL/COMMERCIAL/UTILITY DISPOSAL WELLS
Cooling Water Return Flow Wells — used to inject water which was
used in a cooling process, both open and closed loop processes.
Industrial Process Water and Water Disposal Wells — used to dispose
of a wide variety of wastes and wastewaters from industrial, commer-
cial, or utility processes. Industries include refineries, chemical plants.
smelters, pharmaceutical plants, laundromats and dry cleaners, tan-
neries, carwashes, laboratories, etc. Industry and waste stream must
be specified (e.g. Petroleum Storage Facility — storage tank condensa-
tion 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.).
Automobile Service Station Disposal Well — repair bay drains connected
to a disposal well. Suspected of disposal of dangerous or toxic wastes.
RECHARGE WELLS
Aquifer Recharge Wells — used to recharge depleted aquifers and may
inject fluids from a variety of sources such as lakes, streams, domestic
wastcwater treatment plants, other aquifers, etc.
Saline Water Intrusion Barrier '.Veils — used to inject water into fresh
water aquifers to prevent intrusion of salt water into fresh water aquifers.
Subsidence Control Wells — used to inject fluids into a non-oil or gas
producing zone to reduce or eliminate subsidence associated with over-
draft of fresh water and not used for the purpose of oil or natural gas
production.
MISCELLANEOUS WELLS
Radioactive Waste Disposal Wells — all radioactive waste disposal wells
other than Class IV wells.
Experimental Technology Wells — wells used in experimental or un-
proven technologies such as pilot scale in-situ solution mining wells in
previously unmined areas.
Aquifer Remediation Related Wells — wells used to prevent, control,
or remediate aquifer pollution, including but not limited to Sueprfund
sites.
Abandoned Drinking Water Wells — used for disposal of waste.
Other Wells — any other unspecified Class V wells: Well type/purpose
and injected fluids must be specified.
Ground Water
Contamination
Potential
Low-Moderate
High
High
High-Low
Low
Low
Unknown
Low-Moderate
Unknown
Moderate
Unknown
Potential Contaminants
Ami-sealing additives, thermal pollution, potential for in-
dustrial spills reaching ground water.
Potentially any fluid disposed by various industries.
suspended solids, alkalinity, sulfate volatile organic
compounds.
Heavy metals, solvents, cleaners, used oil and fluids,
detergents, organic compounds.
Variable: water is generally of good quality
Varies: advanced treated sewage, surface urban and
agricultural runoff, and imported surface waters.
No specific :ype of injected fluid noted, similar to aquifer
recharge wells.
Low-level radioactive wastes.
Varies depending on project.
Nutrients used in Biodegradation of organics. oil/grease,
phenols, toluene.
Potentially any kind of fluid, particularly brackish or saline
water, hazardous chemcials and sewage.
Variable
EPA
Well
Code
5AI9
sw:o
5X28
5R2!
5B22
5S23
5N24
5X25
5X26
5X29
5X27
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