CSG Law Alert: NJDEP Publishes Adopted Groundwater Quality Standards
On February 3, 2025, the New Jersey Department of Environmental Protection (NJDEP) published the updated Class IIA Ground Water Quality Standards (GWQS), N.J.A.C. 7:9C, originally proposed on January 2, 2024 and formally adopted on January 2, 2025. The new standards have the potential to impact ongoing and completed remediations at sites throughout New Jersey.
When originally published, the Department sought to update the specific ground water quality criteria and/or practical quantitation levels (PQLs) for 73 constituents of Class II-A ground water. The updates were reportedly based on United States Environmental Protection Agency (USEPA) methodologies and the best available scientific information. The adopted version resulted in changes to 64 of the 73 originally identified constituents, of which 52 became more stringent and 12 became less stringent. The other nine constituents remained less than or equal to their PQLs, therefore no change was made. Some of the more commonly encountered contaminants for which there are now updated GWQSs include:
Benzene: 0.45 ug/l (ppb)
Perfluorononanoic acid (PFNA): 0.013 ug/l
Tetrachloroethene: 0.4 ug/l
Trichloroethene: 0.28 ug/l
Vinyl Chloride: 0.035 ug/l
Significantly, the newly published GWQSs changed the following seven contaminants by an order of magnitude or more, thereby potentially triggering reopeners for those sites where they were previously detected in the ground water:
Contaminant Old GWQS New GWQS
1,1 biphenyl 400 ug/L 5.0 ug/L
Cobalt 100 ug/L 2.0 ug/L
Cyanide 100 ug/L 5.0 ug/L
1,3-dichlorobenzene 600 ug/L 5.0 ug/L
Heptachlor epoxide 0.2 ug/L 0.02 ug/L
Methoxychor 40 ug/L 0.1 ug/L
Vinyl Chloride 1.0 ug/L 0.035 ug/L
The NJDEP’s Remediation Standards allow for the existing GWQS to be used for six months, except where the GWQS has decreased by more than an order of magnitude. With respect to reopeners, for cases that have received a final remediation document (e.g., Response Action Outcome), the timing of a reopener analysis depends on whether the site has a restricted, limited restricted, or unrestricted use remedy. For sites that have implemented a restricted or limited restrictive use remedy (e.g., utilizing institutional control and/or engineering control), the order of magnitude evaluation would be part of the required biennial remedial action protectiveness certification. For sites that have implemented an unrestricted use remedy, the order of magnitude evaluation would be required at the time when a future compliance obligation is triggered, such as compliance with the Industrial Site Recovery Act (N.J.S.A. 13:1K-6 et seq.).
The order of magnitude evaluation would be conducted pursuant to the Technical Requirements for Site Remediation at N.J.A.C. 7:26E-3.2(a) and cases with an existing Remedial Action Workplan involving a parameter with an update of less than one order of magnitude change will be grandfathered.