On May 5, 2015, the New York Court of Appeals upheld a 2010 general permit issued by the New York State Department of Environmental Conservation (NYSDEC) for municipal separate storm sewer systems (known as MS4s).  The case,  In The Matter of Natural Resources Defense Council, Inc. v NYSDEC, 2015 NY Slip Op 03766, pitted several environmental organizations led by the Natural Resources Defense Council, Inc. (NRDC) against the NYSDEC. The 2010 general permit (a 5-year permit) applies to systems that serve municipalities with populations less than 100,000.  There are approximately 500 municipal systems in New York State that fall within this category.

NRDC argued that the general permit violates the federal Clean Water Act because it fails to ensure that these small municipalities reduce their pollutant discharges to the “maximum extent practicable.” NRDC also argued that the general permit is a self-regulatory system that fails to provide for adequate review and oversight by the NYSDEC to confirm compliance with the general permit and fails to provide an opportunity for a public hearing on a municipality’s plan to control storm water discharge.

The NYSDEC countered by contending that the general permit requires covered municipalities to develop, document and implement a storm water management plan (SWMP) that includes 44 mandatory best practices grouped into six categories of control measures.  The general permit also requires these municipalities to compile maps that show locations of all outfalls and field-verify them. The municipalities also have to develop procedures to identify areas of greatest concern, identify and eliminate illicit discharges, and document their implementation of their SWMP.  NYSDEC also argued that the general permit requires the municipality to commit to each mandated, and any optional best management practice, in its  SWMP.  Furthermore, the municipality must file a 19-page Notice of Intent (NOI) to be covered by the general permit, which is reviewed for completeness by the NYSDEC and is made available for a 28-day public comment period.

The Court of Appeals, in a 4-3 split decision, sided with the NYSDEC and all of the municipalities subject to the general permit.  The majority found that the NYSDEC review of the NOI is a sufficient technical regulatory review and that the public has an adequate opportunity to review and comment on the SWMP and NOI.  The majority determined that it would not second-guess the experience and expertise of the NYSDEC in administering the MS4 program under the applicable statutes and regulations.

The 2010 general permit expired on April 30, 2015.  Since the case was still pending at the time, the NYSDEC enacted a 2-year interim general permit in April 2015, which became effective on May 1, 2015.  That interim permit made no substantive changes to the MS4 program and none are expected in the near future, given the NYSDEC’s victory at the Court of Appeals.