EPA Region 1 has issued a Preliminary Designation of stormwater discharges from commercial, industrial, and institutional properties with one or more acres of impervious surface in the Charles, Neponset, and Mystic River watersheds in Massachusetts for NPDES regulation under Clean Water Act residual designation authority. Simultaneously, EPA released a Draft CII General Permit requiring permittees to develop Stormwater Pollution Control Plans and achieve phosphorus reductions of 65%, 62%, and 60% in the Charles, Mystic, and Neponset watersheds respectively. The public comment period runs through January 29, 2025, with virtual meetings and hearings in January 2025.1