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Ground Water Quality Standards

The Ground Water Quality Standards (GWQS), N.J.A.C 7:9C, establish the designated uses of the State's ground waters, classify ground waters based on those uses, and specify the water quality criteria and other policies and provisions necessary to attain those designated uses. The ground water quality criteria are numerical values assigned to each constituent (pollutant) discharged to ground waters of the State. The GWQS also contain technical and general policies to ensure that the designated uses can be adequately protected. Ground water is classified according to its hydrogeologic characteristics and designated uses. 

Designated uses are assigned as primary or secondary uses of ground water and include maintenance of special ecological resources, provision of and conversion to potable water, agricultural and industrial water supply, and other reasonable uses (other than potable use). For all ground waters of the State, the GWQS assign designated uses of the ground water within each classification (see N.J.A.C. 7:9C- 1.5), and establish numerical water quality criteria to support those uses (see N.J.A.C. 7:9C-1.7). The GWQS also establish antidegradation policies (see N.J.A.C. 7:9C-1.8), which are designed to protect the existing and designated uses of the State's ground waters.

Proposed and adopted amendments to the GWQS rules from 2004 through the present, and their corresponding basis and background documents, are available on the Rule Archives Web page.

Ground Water Classifications

The GWQS establish three major classes of ground water: Class I Ground Water of Special Ecological Significance, Class II Ground Water for Potable Water Supply, and Class III Ground Water With Uses Other Than Potable Water Supply.

  1. Class I Ground Water of Special Ecological Significance: Class 1 includes ground water within watersheds of FW1 surface waters, State-owned Natural Areas, and the major aquifers of the Pinelands Area.  The designated use for Class I ground water is the maintenance of special ecological resources.  Secondary uses include potable, agricultural and industrial water.

  2. Class II Ground Water: Class II ground waters include all areas that are not designated as Class I or Class III. The designated use of Class II ground waters is to provide potable water using conventional treatment.  Both existing and potential potable water uses are included.
  3. Class III ground water: Class III ground waters can be used for anything other than for potable water. For Class III ground water, where existing ground water quality is better than the ground water quality criteria, the GWQS allow degradation of ground water quality up to the applicable criteria.

Ground Water Classification Maps

Ground Water Quality Criteria

The GWQS establish ground water quality criteria (see N.J.A.C. 7:9C-1.7) for the different ground water classifications:

  1. Class I Ground Water: Ground water quality criteria for Class 1 ground water is natural quality for each constituent in Class I-A and Class I-PL (Pinelands Preservation Area) ground water, and background water quality for Class I-PL (Pinelands Protection Area) ground water. Class 1 ground waters are nondegradation waters.

  2. Class II Ground Water: Class II ground water quality criteria specify the levels of constituents above which would pose an unacceptable risk for using ground water for drinking water purposes. Appendix Table 1 of the GWQS and the Interim Ground Water Quality Criteria posted on this Web site specify the ground water quality criteria, including health-based criteria and Practical Quantitation Levels (PQLs), for all Class-IIA ground waters. The applicable ground water quality standard for a particular constituent is the higher of the PQL and the ground water quality criterion.


  3. Class III Ground Water: The ground water quality criteria for Class III-A ground water is the Class II-A criteria. The ground water quality criteria for Class III-B ground water is established on a site-specific basis.
Class II A - Ground Water Quality Criteria

Class IIA ground water quality criteria may be established as specific criteria, interim specific criteria, or interim generic criteria, as explained below.

Specific ground water quality criteria for Class II-A ground waters (most of the State's ground waters are classified as II-A ground waters) are listed in Appendix Table 1 of the GWQS. Since Class II-A ground waters have been designated for potable (i.e., drinking water) use, health-based criteria have been developed to protect public health without consideration of analytical feasibility, treatability, and cost. The health-based criteria reflect the most recent toxicological information to ensure adequate protection.

Interim specific ground water quality criteria are posted on the Department's Web site in the Interim Ground Water Quality Criteria Table. The Department generally establishes new ground water quality criteria through amendments to or readoption of the GWQS rules. However, the GWQS rules at N.J.A.C. 7:9C-1.7(c) allow the Department to establish new ground water quality criteria on an interim basis prior to rulemaking. The Department may establish interim specific ground water quality criteria for constituents that are not listed on Appendix Table 1 when sufficient health-based information is available to derive a criterion and practical quantitation limit (PQL) in accordance with the methodologies or risk assessment approach discussed in N.J.A.C. 7:9C-1.7(c)2, 3 and 4.

Interim generic ground water quality criteria are provided in Appendix Table 2 of the GWQS. If the Department determines that insufficient information is available to derive a health-based interim specific criterion for a Synthetic Organic Chemical (SOC) that is not listed on Appendix Table 1, the interim generic ground water quality criteria listed in Appendix Table 2 of the GWQS applies, based on the Department's determination of carcinogenicity for that constituent.

Where a health-based criterion (specific, interim specific, or interim generic) is not achievable within current analytical methods, the applicable ground water quality standard for the constituent is represented by the PQL.

The Interim Ground Water Quality Criteria Table identifies all of the SOCs for which an interim specific ground water quality criterion is currently in effect, as well constituents with insufficient information to develop a health-based criterion but for which an interim generic criterion was selected based on the Department's determination of carcinogenicity. This table is periodically updated to reflect any changes made to the interim ground water quality criteria based on the most current scientific information available to the Department. The Department endeavors, with each major rulemaking, to replace interim criteria with specific criteria wherever there is a scientific basis for such action. (See the Department's rule archives for previous proposals and adoptions where former interim criteria were adopted as specific criteria in the GWQS rules.)

Updating Ground Water Quality Criteria

The Department may update specific ground water quality criteria listed in Appendix Table 1 through rulemaking. Rule proposals, along with any basis and background information, are published in the New Jersey Register and posted on the Department's Rules and Regulations Web page, unless the criteria can be established as Interim Specific Ground Water Quality Criteria or revised through an Administrative Change, as explained below.

Establishing Interim Specific Ground Water Quality Criteria

The GWQS rules at N.J.A.C. 7:9C-1.7(c)2 state that the Department may establish interim specific ground water quality criteria for constituents not listed on Appendix Table 1 of the GWQS by posting them on the Department's Web site along with supplemental information used in their derivation. The Department posts these interim specific ground water quality criteria on the Interim Ground Water Quality Criteria Table, which is updated as new information becomes available.

Administrative Change

The Department may also update the ground water quality criteria listed at Appendix Table 1 of the GWQS through an administrative change to the rules when the USEPA revises the carcinogenic slope factor or reference dose data contained in the USEPA Integrated Risk Information System (IRIS) database on which a specific ground water quality criterion in Appendix Table 1 is based, or when the Department adopts a new or revised Maximum Contaminant Level (MCL) in the Safe Drinking Water Rules at N.J.A.C. 7:10. Ground water quality criteria revised as an administrative change are updated in Appendix Table 1 upon filing with the Office of Administrative Law. Notices of Administrative Change are posted on the Department's Rules and Regulations Web page for six months.

Compendium of Standards

The Department has developed an electronic compendium of standards for water and soil promulgated by the New Jersey Department of Environmental Protection. Included are Surface Water Quality Standards, N.J.A.C. 7:9B; Ground Water Quality Standards, N.J.A.C. 7:9C; Drinking Water Quality Standards, N.J.A.C. 7:10; and soil remediation standards from the Remediation Standards, N.J.A.C. 7:26D. The compendium includes the standards and information about the basis for the standards contained in the above referenced rules. The standards in these rules are used by the Department's regulatory programs to establish site-specific requirements in accordance with the appropriate regulations. Please refer to the official versions of these rules for the most accurate information about the standards currently in effect and how they are administered by the Department. Information on obtaining the official versions of Department rules is available on the Department's Web site at http://www.state.nj.us/dep/legal/get_rule.htm.

Frequently Asked Questions

The Department has developed Frequently Asked Questions (FAQ) on the GWQS to answer general questions about implementation of the GWQS through regulatory programs such as Site Remediation and NJPDES. Questions concerning the application of the GWQS to contaminated sites should be directed to the case manager assigned to the site.

For more information about the GWQS Program, please contact the Bureau of Water Quality Standards and Assessment, at (609) 777-1753.

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Department of Environmental Protection
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Last Modified: April 13, 2010

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