Effective February 3, 2025, the New Jersey Department of Environmental Protection (NJDEP) adopted amendments to the Ground Water Quality Standards (GWQS), N.J.A.C. 7:9C. The amendments updated the groundwater quality criteria and/or practical quantitation levels (PQLs) for 73 constituents, the vast majority of which became more stringent. For example, groundwater quality standards for tetrachloroethylene (PCE) and vinyl chloride were changed from 1 µg/l to 0.4 µg/l and 0.035 µg/l, respectively. Of note, the decrease attributable to vinyl chloride is by more than an order of magnitude – a significant and regulatorily meaningful change. NJDEP also amended its rounding protocols to round new or revised groundwater standards to two significant figures rather than one. The amendments enable NJDEP to update specific groundwater criteria for constituents with corresponding Safe Drinking Water Act (SDWA) maximum contaminant levels (MCLs) when NJDEP determines the weight of evidence approach would more appropriately address risks posed by such constituents than the health-based levels used to establish MCLs.

NJDEP’s amendments may have substantial impacts on current and new remediation projects and may prolong the process for obtaining case closure. By moving the goalposts in such a manner, projects that were set to achieve remediation standards and obtain closure may need to continue remediation activities for a longer period of time to meet the newly adopted levels, which, as mentioned above, may in some cases be by more than an order of magnitude more stringent than the previously established ones. This may likely lead to increased remediation costs and efforts for property owners.

For more information regarding these amendments, please contact Andrew Perel or Buck Dixon.