EPA Proposes Updates To NPDES Definitions And Exclusions

On September 4, 2026, EPA published a proposed rule to revise the regulatory definition of “discharge of a pollutant” to accurately implement the statutory exclusion of vessels and other floating craft that add pollutants in the contiguous zone or the ocean. 91 Fed. Reg. 56819 (Sept. 4, 2026). As a result, such discharges would be expressly excluded from the regulatory definitions of “discharge of a pollutant” and “discharge” and would not be subject to National Pollutant Discharge Elimination System (NPDES) program requirements. While this proposal might catch the attention of the operators of certain maritime vessels or platforms, such as Mobile Offshore Drilling Units (MODUs), that are sometimes treated as a vessel and sometimes as a point source, it is important to note that EPA’s proposed rule states that the “primarily potentially affected operations” are offshore seafood harvesting and processing from vessels that discharge in the contiguous zone or the ocean, and that