US EPA's Program to
Regulate the Placement
of Waste Water and other
Fluids Underground
SAFE DRINKING WATER ACT • 1974-2004 • PROTECT OUR HEALTH FROM SOURCE TO TAP
Why Do We Need a Program to
Regulate the Placement of Fluids
Underground?
Facilities across the nation discharge a variety of
hazardous and nonhazardous fluids into underground
formations through more than 800,000 injection
wells. Our way of life would be quite different without
injection wells. Agribusiness and the chemical and
petroleum industries as we know them today, could
not exist. While treatment technologies exist, it would
be cost prohibitive to treat and release to surface
waters the trillions of gallons of wastes that industries
produce each year. When wells are properly sited,
constructed, and operated, underground injection is
an effective and environmentally safe alternative to
surface disposal.
The Underground Injection Control (UIC) Program
provides these safeguards so that injection wells do
not endanger drinking water. The most accessible
fresh water is stored in shallow geological formations
called aquifers and is the most vulnerable to
contamination. These aquifers feed our lakes;
provide recharge to 41 percent of our streams and
rivers, particularly during dry periods; and serve as
resources for 89 percent of public water systems in
the United States.
What Is an Injection Well?
An injection well is used for subsurface emplacement
of fluids. An injection well is a bored, drilled, or
driven shaft whose depth is greater than the largest
surface dimension; or, a dug hole whose depth is
greater than the largest surface dimension; or, an
improved sinkhole; or, a subsurface fluid distribution
system. This definition covers a wide variety of
injection practices that range from more than
140,000 technically sophisticated highly monitored
wells which pump fluids into isolated formations up
to two miles below the Earth's surface, to the far
more numerous on-site drainage systems, such as
septic systems, dry wells, and storm water wells, that
discharge fluids a few feet underground.
How Does the UIC Program
Regulate the Very Different Types of
Underground Injection?
United States En ivron mental Protection Agency
groups underground injection into five classes for
regulatory control purposes. Each class includes
wells with similar functions, and construction and
operating features
so that technical
requirements can be
applied consistently
to the class.
• Class I injects
hazardous and
nonhazardous
fluids (industrial
and municipal
wastes) into
isolated formations
beneath the
lowermost
u ndergrou nd
source of drinking
water (USDW).
Because they may
inject hazardous
waste, Class I
wells are the most
strictly regulated and are further
regulated under the Resource,
Conservation and Recovery Act.
• Class II includes injection of brines and other
fluids associated with oil and gas production.
• Class III injects fluid associated with solution
mining of minerals.
• Class IV addresses injection of hazardous or
radioactive wastes into or above a USDW and is
banned unless authorized under other statutes for
ground water remediation.
• Class V includes all underground injection not
included in Classes I-IV. Generally, most Class V
wells inject nonhazardous fluids into or above a
USDW and are on-site disposal systems, such as
floor and sink drains which discharge to dry wells,
septic systems, leach fields, and drainage wells.
Injection practices or wells which are not covered
by the UIC Program include single family septic
systems and cesspools as well as non-residential
septic systems and cesspools serving fewer than
20 persons that inject ONLY sanitary waste water.
CLASS I WELL
-------
Are All Injection Wells Waste
Disposal Wells?
All injection wells are not waste disposal wells.
some Class V wells, for example, inject surface
water to replenish depleted aquifers or to prevent
salt water intrusion. Some Class II wells inject fluids
for enhanced recovery of oil and natural gas, and
others inject liquid hydrocarbons that constitute our
nation's strategic fuel reserves in times of crisis. But
most injection wells have the potential to inject fluids
that may cause a
public water system
to violate National
Drinking Water
Standards. These
standards provide
our safety net
against waterborne
disease and other
health risks.
How Does US EPA's UIC Program
Prevent Contamination of Our Water
Supply?
In general, US EPA's UIC Program prevents
contamination of water supplies by setting minimum
requirements for state UIC Programs. A basic concept
of US EPA's UIC Program is to prevent contamination
by keeping injected fluids within the intended injection
zone, or in the case of injection directly or indirectly
into a USDW, the fluids must not endanger or have
the potential to endanger a current or future public
water supply. Most of the minimum requirements that
affect the siting of the injection well, the construction,
operation, maintenance, monitoring, testing, and
finally, the closure of the well, are designed to
address these concepts. Another basic concept is that
all injection wells require authorization under general
rules or specific permits. Finally, states are expected
to have primary enforcement authority (primacy)
for the UIC Program. To date, 33 states, Guam,
Commonwealth of the Mariana Islands, and Puerto
Rico have obtained primacy for all classes of injection
wells. Seven states share primacy with US EPA. The US
EPA administers UIC programs for the remaining ten
states, and all other federal jurisdictions and Indian
Cou ntry.
The UIC Program Protects More Than
Ground Water
The UIC Program:
• Reduces human exposure to organic and
inorganic chemicals and heavy metals by removing
them from the environment;
• Eliminates more than nine billion gallons of
hazardous waste and a trillion gallons of oil field
waste from the environment each year;
CLASS V WELL - Aquifer Remediation Well
•Decreases public water system costs for water
treatment;
• Avoids cost of ground water remediation,
medical monitoring for health effects, and
replacing a drinking water supply;
• Reduces pollution in wellhead and source water
protection areas, rivers, streams, lakes, wetlands,
watersheds, estuaries and coastal zones; and
• Enables communities to make wise local land
use decisions.
For More Information
To learn more about underground injection control,
call the Safe Drinking Water Hotline at 1-800-426-
4791 or visit the safewater web site at www.epa.
gov/safewafer.
Office of Water (4606)
www.epa.gov/safewater
EPA 816-F-04-040 June 2004
------- |