Protecting Underground Drinking Water

About 44 percent of the US population rely on groundwater for their drinking water supply, according to the National Groundwater Association. To protect human health, the Safe Drinking Water Act (SDWA) requires the Environmental Protection Agency (EPA) to establish acceptable quality standards for public drinking water supplies and programs for the protection of underground drinking water supplies.

The EPA's primary program for protecting underground drinking water supplies is the Underground Injection Control (UIC) program (40 CFR 144-148). The UIC program prohibits the unpermitted "subsurface emplacement of 'fluids' through a 'well.'" In this context, "fluid" "means any material or substance which flows or moves whether in a semi-solid, liquid, sludge, gas, or any other form or state," while a "well" is defined as "a bored, drilled or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension." [40 CFR 144.3] Different types of injection wells present different hazards to underground sources of drinking water (USDW). As of 2010, the EPA has regulations for six classes of wells under the UIC program:   Class I [40 CFR 144.6(a)]

• Used to inject hazardous and other wastes below the lowermost underground source of drinking water (USDW)
• The most stringently regulated, under both the UIC program and the hazardous waste regulations
• 680 operational across the United States

Class II [40 CFR 144.6(b)]

• Used to inject brines and other fluids from oil and gas production back into the ground
• Some are authorized by rule, rather than individually permitted
• Over 172,000 operational across the United States

Class III [40 CFR 144.6(c)]

• Used to inject steam or fluids into salt, copper, uranium and sulfur formations to help with extraction
• Nearly 50% of all the salt and 80% of all the uranium extraction in the US accomplished with these wells
• Over 22,000 operational across the United States

Class IV [40 CFR 144.6(d)]

• Used to inject hazardous, radioactive, and other wastes into or above any USDW
• Banned in 1984, unless part of an EPA- or State-authorized groundwater remediation project
• Generally authorized by rule, but states may require permits
• 33 operational around the United States

Class V [40 CFR 144.6(e)]

• Do not fall under Classes I-IV or VI, which inject non-hazardous fluids
• Includes shallow stormwater drainage wells, septic tanks, and cesspools, but also some aquifer storage and geothermal fluid injection wells
• Authorized by rule; no individual permit required, but operators required to protect underlying groundwater
• Over 400,000 operational in the United States (possibly up to 650,000)

Class VI [40 CFR 144.6(f)]

• Used for geologic sequestration of carbon dioxide (CO₂)
• Until 2010, regulated as Class V experimental wells
• Approximately 10 operational in the United States by 2016

Excluded Injection Wells

The following units are excluded from the UIC program:

• Injection wells located on off-shore platforms (outside a state's territorial waters)
• Residential waste disposal systems (single family only)
• Small non-residential waste disposal systems
• Injection wells used to store natural gas
• Dug holes that are not used to emplace fluids underground

As with most EPA regulations, states are allowed to create and manage their own UIC regulatory programs, provided the State program is at least as stringent (protective of the environment) as the Federal rules. Once the state's UIC program is approved by the EPA, primacy for running and enforcing the program shifts to the state. Currently, 33 states, three territories, and two tribal nations have their own UIC programs. The EPA shares primacy with seven other states and has full primacy in the remaining ten, per this map.

Expert Training on EPA Rules

Be confident your team is prepared to comply with the latest requirements for protecting human health and the environment under the Safe Drinking Water Act. Lion's Complete Environmental Regulations Workshop is presented in cities nationwide and covers the critical elements of the EPA's air, water, and chemical rules. Designed for environmental managers, plant engineers and managers, and corporate attorneys, the two-day workshop will help you identify your legal requirements under the Clean Air Act, Clean Water Act, SDWA, FIFRA, TSCA, and more as required for ISO 14000.

Tags: EPA, Safe Drinking Water Act, state rules