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Selecting a Groundwater Remedy

There is no one approach to addressing groundwater contamination. Early in the assessment and planning phases of a cleanup, EPA evaluates a range of remedies consistent with CERCLA, the NCP and EPA. The cleanup approaches are re-evaluated throughout cleanup as remedy effectiveness is evaluated and site conditions change. If appropriate, remedies may change. The following section provides guidance and policy for selecting groundwater response actions.

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Groundwater Restoration Policy Summary

Summary of Key Existing EPA CERCLA Policies for Groundwater Restoration (PDF)(12 pp, 2.3 MB)
June 2009, OSWER Directive 9283.1-33

This memorandum provides a compilation of some key EPA groundwater policies to assist EPA regional offices in making groundwater restoration decisions in accordance with Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). It addresses:

  • Whether CERCLA remedial action is warranted;
  • Appropriate role of institutional controls;
  • Groundwater classification and beneficial use policy;
  • Remedial action cleanup levels; and
  • Groundwater point of compliance.

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Groundwater Removal Actions

Regional Removal Management Levels for Chemicals (RMLs) Web Area

Regional Removal Management Levels for Chemicals (RMLs) were developed to assist On-Scene Coordinators (OSCs) and others involved in decision-making concerning CERCLA removal actions at Superfund sites. The RMLs serve as an update to the previous lists of Removal Action Levels (RALs) and reflect changes in Agency toxicity criteria and risk methodologies. The RML web area provides information regarding current RMLs, including a user’s guide and frequently asked questions. The RMLs are updated on a biannual basis.

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Applicable or Relevant and Appropriate Requirements (ARARs) for Ground Water Cleanups

All CERCLA-selected remedial actions must, at a minimum, attain or waive ARARs to assure an implemented remedy is protective of human health and the environment. The following section provides guidance for ARARs for groundwater cleanups.

Applicability of RCRA Section 3020 to In-Situ Treatment of Ground Water (PDF) (6 pp, 388 K)
December 2000
Attachment: Applicability of Land Disposal Restrictions to RCRA and CERCLA Ground Water Treatment Reinjection Superfund Management Review: Recommendation No. 26 (PDF) (3 pp, 317 K)
December 1989, OSWER Directice 9234.1-06

This memorandum clarifies that reinjection of treated groundwater to promote in-situ treatment is allowed under section 3020(b) as long as certain conditions are met.

Applicability of Land Disposal Restrictions to RCRA and CERCLA Groundwater Treatment Reinjection Superfund Management Review: Recommendation No. 26 (PDF) (3 pp, 317 K)
December 1989, OSWER Directice 9234.1-06

This memorandum explains EPA’s interpretation of whether Resource Conservation and Recovery Act (RCRA) land disposal restrictions are applicable or, under CERCLA response actions only, relevant and appropriate to reinjections or to the remediation as a whole.

Clarification of the Role of Applicable, or Relevant and Appropriate Requirements in Establishing Preliminary Remediation Goals Under CERCLA (PDF) (4 pp, 411 K)
August 1997, OSWER Directive 9200.4-23

This memo clarifies the relationship between ARARs and protectiveness.

Permits and Permit 'Equivalency' Processes for CERCLA On-site Response Actions (PDF)(7 pp, 45 K)
February 1992, OSWER Directive 9355.7-03

Clarifies the EPA policy on ARARs with respect to attaining permits for activities at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites.

ARARs Q & A's

ARARs Q's & A's: Compliance with New SDWA National Primary Drinking Water Regulations for Organic and Inorganic Chemicals (PDF)(11 pp, 853 K)
August 1991, OSWER Publication 9234.2-15/FS

This document provides answers to questions that arose in developing ARAR policies and training sessions, and in identifying and complying with ARARs at specific sites. It also addresses compliance with Safe Drinking Water Act (SDWA) regulations promulgated in 1991.

ARARs Q's & A's: General Policy, RCRA, CWA, SDWA, Post-ROD Information, and Contingent Waivers (PDF)(5 pp, 84 K)
July 1991, OSWER 9234.2-01FS-A

This document updates and replaces a document issued in May 1989.

ARARs Q's & A's: State Ground-Water Antidegradation Issues (PDF)(9 pp, 832 K)
July 1990, OSWER 9234.2-11FS

This document provides guidance on state groundwater antidegradation provisions as potential ARARs for CERCLA groundwater and soil cleanups, and how those provisions relate to EPA’s policy of returning usable groundwater to its beneficial uses within a reasonable timeframe.

ARARs Q's & A's: Compliance with Federal Water Quality Criteria (PDF)(9 pp, 695 K)
June 1990, OSWER 9234.2-09FS

This Q & A addresses compliance with federal water quality criteria as ARARs.

CERCLA Compliance with Other Laws Manual: Part I, Interim Final (PDF)(243 pp, 1.8 MB)
August 1988, OSWER Publication 9234.1-01

CERCLA Compliance with Other Laws Manual: CERCLA Compliance with the CWA and SDWA Fact Sheet (PDF)(7 pp, 688 K)
February 1990, OSWER 9234.2-06FS

Section 121(d) of CERCLA requires that on-site remedial actions attain or waive federal or more stringent state ARARs upon completion of the remedial action. The 1990 NCP requires compliance with ARARs during remedial actions, and during removal actions to the extent practicable. These documents cover potential ARARs under the major environmental statutes and other laws. The 1990 fact sheet provides a guide to Chapters 3 and 4 of Part I of the "CERCLA Compliance with Other Laws Manual." The fact sheet focuses on CERCLA compliance with the Clean Water Act (Chapter 3) and Safe Drinking Water Act (Chapter 4), and discusses other statutes with provisions relevant to surface water or drinking water.

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Alternative Water Supply

Update on Providing Alternative Water Supply as Part of Superfund Response Actions (PDF)(8 pp, 4.5 MB)
September 2010, OSWER Directive 9355.3-22

This memorandum modifies the February 1988 guidance (see next reference) by no longer recommending the use of two types of alternative water supply options described in that guidance, specifically: 1) oversized community storage facilities to compensate for loss of existing system capacity in emergency demand situations and, 2) blending of new and existing water supplies to achieve acceptable levels. This memorandum also provides a summary of remedial and removal actions that included alternative water supplies and the number of people protected.

Guidance Document for Providing Alternate Water Supplies (PDF)(71 pp, 2 MB)
February 1988, OSWER Directive 9355.3-03, EPA/540/G-87/006

This guidance helps response managers plan and implement alternate water supplies at uncontrolled hazardous waste sites under a non-time-critical removal action or an operable unit (or “early”) remedial action. It also provides guidance on determining if an alternate supply is needed. Appendix C on EPA Standards and Appendix D on Removal Action Levels have been superseded by more recent standards and guidance.

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Groundwater Use Determinations

How current and future use of groundwater are determined may be based on EPA designation or designation or by state or tribal authorities. EPA recognizes the central role of the states and tribes in making groundwater protection decisions; if a state has an EPA approved Comprehensive State Groundwater Protection Plan or other codified groundwater standards that meet the regulatory criteria, those are the standards that will drive the groundwater cleanup. The section provides guidance on groundwater use determinations.

The Role of CSGWPPs in EPA Remediation Programs (PDF)(16 pp, 235 K)
April 1997, OSWER Directive 9283.1-09

This directive establishes and explains the policy that EPA remediation programs generally should defer to state determinations of current and future groundwater uses when based on an EPA-endorsed comprehensive state groundwater protection program (CSGWPP). This directive also provides background information on CSGWPPs.

Final Comprehensive State Ground Water Protection Program Guidance (PDF)(166 pp, 850 K)
December 1992, EPA 100-R-93-001

This document provides guidance to states on preparing comprehensive state groundwater protection programs in order to coordinate groundwater protection across programs and provide additional flexibility to states in directing their groundwater activities.

Guidelines for Ground-Water Classification Under the EPA Groundwater Protection Strategy (PDF)(10 pp, 437 K)
November 1986, EPA 440-6-86-007

These final draft guidelines further define the concepts and key terms related to the classification system outlined in the 1984 Groundwater Protection Strategy, and describe procedures and information needs for classifying groundwater using this approach. Although the guidelines were not finalized, they are still in current use, as modified by the more recent CSGWPP guidance documents referenced above.

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Technical Impracticability

EPA recognizes that it may not be possible to restore groundwater to its designated beneficial use in some cases. In situations where, from an engineering perspective, it is not possible to restore all or part of a groundwater plume, EPA may waive applicable or relevant and appropriate requirements (ARARs) and establish alternative, protective remedial strategies. The following section provides guidance relating to technical impracticability of groundwater restoration.

Clarification of the Consultation Process for Evaluating the Technical Impracticability of Groundwater Restoration at CERCLA Sites (PDF)(20 pp, 628 K)
December 2016, OLEM Directive 9200.3-117

This directive is an extension of the original 1993 OSWER Directive 9234.2-25, Guidance for Evaluating the Technical Impracticability (TI) of Ground-Water Restoration, and the subsequent 1995 OSWER Directive 9200.4-14, Consistent Implementation of the FY 1993 Guidance on Technical Impracticability of Ground-Water Restoration at Superfund Sites.

The six documents in this TI package are designed to help:

  • Promote national consistency;
  • Facilitate transfer of information between EPA headquarters and regional offices;
  • Identify the appropriate persons to conduct document reviews; and
  • Clarify the role of headquarters consultation.

Summary of Technical Impracticability Waivers at National Priorities List Sites (PDF)(101 pp, 1.7 MB)
August 2012, OSWER Directive 9230.2-24

The report provides the rationale for adopting a TI waiver, and includes summaries of site conditions and EPA-issued TI waivers.

Clarification of OSWER's 1995 Technical Impracticability Waiver Policy (PDF)(4 pp, 764 K)
September 2011, OSWER Directive 9355.5-32

This memorandum clarifies the July 1995 memorandum referenced directly below regarding the use of TI waivers at CERCLA sites with dense non-aqueous phase liquid (DNAPL) contamination.

Superfund Groundwater RODs: Implementing Change This Fiscal Year (PDF)(2 pp, 33 K)
July 1995, OSWER 9335.5-03P, EPA 540-F-99-005

This memorandum discusses the importance of consistent national implementation of policies concerning sites with groundwater contamination. It emphasizes that TI waivers will generally be appropriate for sites where restoration of groundwater to drinking water standards is technically impracticable. This document was updated by the above-referenced September 2011 document titled "Clarification of OSWER's Technical Impracticability Waiver."

Consistent Implementation of the FY 1993 Guidance on Technical Impracticability of Ground-Water Restoration at Superfund Sites (PDF)(7 pp, 388 K)
January 1995, OSWER Directive 9200.4-14

This document clarifies the role of EPA headquarters in groundwater TI decisions and emphasizes that these decisions should be made as soon as sufficient information is available.

Guidance for Evaluating Technical Impracticability of Ground-Water Restoration (PDF)(27 pp, 2.4 MB)
September 1993, OSWER Directive 9234.2-25

This interim final guidance clarifies how EPA will determine whether groundwater restoration at Superfund and RCRA sites is technically impracticable and if so, what alternative measures are needed to ensure that a final remedy is protective.

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Phased Ground Water Cleanup Approach

Using a phased cleanup approach, site response activities are implemented in a sequence of steps, or phases, such that information gained from earlier phases is used to refine subsequent investigations, objectives, or actions. Phased remedy approaches may include the implementation of early and interim actions. A phased approached may be most appropriate with varied degrees of contamination over the area of the site. The following section provides guidance on the phased cleanup approach for groundwater cleanup.

Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated Ground Water at CERCLA Sites (PDF)(86 pp, 779 K)
October 1996, OSWER Directive 9283.1-12

This guidance outlines the "phased approach" strategy for addressing contaminated groundwater. The strategy emphasizes ways to select achievable remedial objectives and optimize the selected remedy so it is more effective, less costly, and takes less time. The guidance also identifies presumptive technologies for treatment of extracted groundwater to streamline the feasibility study for sites where pump-and-treat remedies are being evaluated.

Considerations in Ground-Water Remediation at Superfund Sites and RCRA Facilities — Update (PDF)(13 pp, 76 K)
May 1992, OSWER Directive 9283.1-06

This directive clarifies and expands the Office of Solid Waste and Emergency Response’s (now the Office of Land and Emergency Management) general policy concerning contaminated groundwater remediation, especially regarding non-aqueous phase liquid contaminants.

Suggested ROD Language for Various Groundwater Remediation Options (PDF)(9 pp, 52 K)
October 1990, OSWER Directive 9283.1-03

This directive provides guidance for Superfund records of decision (RODs) concerning groundwater. The guidance recommends remedies be defined as:

  • Final actions where there is little uncertainty that the remedy will be able to achieve remediation goals;
  • Contingency measures or goals where there is high to moderate uncertainty, potential applicable or relevant and appropriate requirements (ARARs) waivers, or a potential containment goal; and
  • Interim actions where there is moderate to substantial uncertainty or early action containment measures.

The guidance includes sample ROD language.

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Remedy Selection and Decision Documents

The following section provides key guidance on selecting and documenting groundwater cleanup decisions.

Use of Monitored Natural Attenuation for Inorganic Contaminants in Groundwater at Superfund Sites (PDF)(83 pp, 1.3 MB)
August 2015, Final OSWER Directive 9283.1-36

This guidance expands on and is designed to be a companion to the April 1999 monitored natural attenuation (MNA) guidance referenced below. Together, these two documents provide guidance on the consideration of MNA for a broad range of contaminants at Superfund sites.

Alternate Concentration Limits (ACLs) in Superfund Cleanups (PDF)(4 pp, 341 K)
July 2005, OSWER Directive 9200.4-39

This memorandum provides EPA policy related to the use of CERCLA ACLs in Superfund cleanups and supersedes any previous guidance on this matter. This memorandum reiterates the statutory requirements and provides several factors to consider when evaluating whether use of CERCLA ACLs may be appropriate under site-specific circumstances.

Alternate Concentration Limit Guidance, Interim Final (PDF)(127 pp,4.5 MB)
July 1987, OSWER Directive 9481.00-6C, EPA 530-SW-87-017

This document provides guidance to RCRA facility permit applicants and writers concerning the establishment of RCRA Alternate Concentration Limits (RCRA ACLs). The guidance lists 19 factors, or criteria, that are used to evaluate ACL requests.
Caution: Information in this document cannot be applied to Superfund sites because the CERCLA statute placed several limitations on the use of ACLs in Superfund remedies (see Alternate Concentration Limits (ACLs) in Superfund Cleanups, OSWER Directive 9200.4-39, above).

Guide to Preparing Superfund Proposed Plans, Records of Decision, and Other Remedy Selection Decision Documents (PDF)(182 pp, 2.9 MB)
July 1999, OSWER Memorandum 9200.1-23P, EPA 540-R-98-031

This document provides guidance on writing Records of Decision (RODs), Explanations of Significant Differences (ESDs) and ROD amendments. It also includes sections on documenting all types of groundwater remedy decisions and technical impracticability waivers, including sample language.

How this document relates specifically to groundwater:

  • Section 9.4 provides specific guidance to documenting groundwater decision responses.
  • Section 9.5 provides guidance on documenting Technical Impracticability waivers.
  • Attachment A provides a sample Proposed Plan that deals with groundwater contamination among other media. Attachment B provides information on documenting special groundwater remedy decisions such as the phase approach.

Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites (PDF)(39 pp, 1.9 MB)
April 1999, OSWER Directive 9200.4-17P, Publication EPA540-R-99-009

This document clarifies EPA's policy regarding the use of monitored natural attenuation for the remediation of contaminated soil and groundwater.

Rules of Thumb for Superfund Remedy Selection (PDF)(27 pp, 152 K)
August 1997, OSWER Publication 9355.0-69, EPA 540-R-97-013

This guidance describes key principles, expectations and best practices based on program experience that should be considered during the Superfund remedy selection process. It covers three major policy areas: risk, remedial alternatives, and groundwater.

Superfund Reforms: Updating Remedy Decisions (PDF)(9 pp, 455 K)
September 1996, OSWER Memorandum 9200.0-22, EPA 540-F-96-026

This memo explains the purpose of the reforms, the types of remedy updates anticipated, and the process for updating remedies. It also explains how the reforms relate to groundwater remedies, particularly remedy updates that change the remediation technology, reconsider remedial objectives, or reduce monitoring data needs.

A Guide to Principal Threat and Low Level Threat Wastes (PDF)(4 pp, 236 K)
November 1991, Superfund Publication 9380.3-06F

This guidance explains considerations for categorizing waste for which treatment or containment generally will be suitable. It provides definitions, examples and Record of Decision documentation requirements related to waste that constitute a principal or low-level threat. It explains that the concept of principal threat is to be applied when characterizing source material and that contaminated groundwater is not generally considered to be a source material, although non-aqueous phase liquids (NAPLs) may be viewed as source materials.

A Guide on Remedial Actions for Contaminated Ground Water (PDF)(5 pp, 101 K)
April 1989, OSWER Directive 9283.1-2FS

This fact sheet summarizes key issues in the development, evaluation and selection of groundwater remedial actions at Superfund sites. For more information, see the December 2008 document directly below. Use of either document should be augmented by more recent guidance.

Guidance on Remedial Actions for Contaminated Ground Water at Superfund Sites (PDF)(121 pp, 1.8 MB)
December 1988, OSWER Directive 9283.1-2, EPA 540-G-88-003

This guidance summarizes policy issues and the decision-making approach to developing, evaluating, selecting and implementing groundwater remedial actions at Superfund sites. Use of this or the preceding document should be augmented by more recent guidance.

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