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.

The New Jersey Department of Environmental Protection posted interim soil remediation standards for several per- and polyfluoroalkyl substances (collectively PFAS) to include perfluoro nonanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluoro octane sulfonate (PFOS), and hexafluoropropylene oxide dimer acid and its ammonium salt (GenX). Posted in the October 17 NJ Register, the interim standards pertain to the direct contact and migration to groundwater exposure paths, and apply immediately.

On January 11, the U.S. Environmental Protection Agency (EPA) issued a new interpretation of its coal combustion residual (CCR) regulations: CCR landfills or surface impoundments “cannot be closed with coal ash in contact with groundwater.” Although EPA claims it has “consistently held” this interpretation, this is the first time EPA has expressly articulated this view. Perhaps acknowledging the novelty of its position, EPA also announced its intent to “review … state-level CCR program applications to ensure they are as protective as federal regulations” and to proceed toward a federal CCR permitting framework.

In a landmark ruling signaling a new lens with which to view the treatment of interstate water allocation, the U.S. Supreme Court issued a decision on November 22 in Mississippi v. Tennessee, et al., 595 U.S. ___ (Case No. 21o143) rejecting Mississippi’s claim to sole ownership of waters of the Middle Claiborne Aquifer within that state’s borders. Instead, the Court held that the traditional remedy of equitable apportionment used to allocate surface waters of streams and rivers should apply. The case represents the first time that the Court has held that equitable apportionment applies to groundwater, which may open the door to new disputes among border states who claim equal rights to underground water resources.

On January 28, the Illinois Environmental Protection Agency (Illinois EPA) announced the issuance of health advisories for four (4) per- and polyfluoroalkyl substances (PFAS) compounds in accordance with the Illinois Part 620 groundwater regulations (35 Ill. Adm. Code Part 620). Health advisories are issued when a chemical substance that is harmful to human health, and for which no numeric groundwater standard exists, is detected and confirmed in a community water supply well (35 Ill. Adm. Code 620.605). The four (4) PFAS compounds for which Illinois health advisories were issued are PFBS, PFHxS, PFHxA, and PFOA.