Legal Terrain

The Basics of Stormwater Permitting in Massachusetts

October 12, 2023


After a summer of historic rainfall and flooding in Massachusetts, stormwater is on our minds. Stormwater is a major source of water pollution in the Commonwealth, and it is crucial that owners and operators of commercial and industrial facilities, land developers, and construction contractors understand the legal framework governing it.

The federal Clean Water Act prohibits the discharge of pollutants into the waters of the United States without a permit. The permitting system established under the act is known as the National Pollutant Discharge Elimination System (NPDES). The EPA has delegated authority over NPDES permitting to most states but not in Massachusetts, meaning the EPA issues NPDES permits for covered persons in Massachusetts.

Several NPDES permits cover stormwater discharges, i.e., runoff from rainfall and snowmelt, depending on the source category. The covered source categories are industrial activities, construction activities, and municipal separate storm sewer systems (MS4s).

Industrial activities are covered under a permit known as the Multi-Sector General Permit (MSGP). The permit covers activities at commercial and industrial facilities that are exposed to the weather. Stormwater that comes in contact with these activities can pick up pollutants and transport them to nearby waters. Covered activities are sorted by industrial sector and include heavy manufacturing, hazardous and solid waste treatment, storage and disposal sites, metal scrapyards and salvage yards, and transportation facilities with vehicle maintenance or equipment cleaning operations.

Construction activities are covered under a separate permit known as the Construction General Permit (CGP). Stormwater washes over loose soil, materials, and products stored on construction sites and can pick up pollutants and transport them to storm sewer systems or directly into nearby waters. Construction activities such as clearing, grading, and excavating land that disturbs 1 acre or more of land (either as one project or as part of a common development plan or sale) require a permit.

Municipal separate storm sewer systems serving municipalities with a population of less than 100,000 are covered by a statewide general permit (Small MS4 General Permit). An MS4 is a system of conveyances for collecting and conveying stormwater (e.g., storm drains, pipes, or ditches) that is owned by a public entity, that is not combined with a sewer or part of a sewage treatment plant, and that discharges to covered waters. System operators are required to obtain a permit and develop stormwater management programs to prevent pollutants from being washed or dumped into MS4s.

State authorization from the Department of Environmental Protection, known as a WM15 application, is also required, but only when stormwater discharges under these NPDES permits are to or near Outstanding Resource Waters (ORW). ORW includes waters that may be used as a public water supply and their tributaries, certain wetlands and surface waters, and other waters determined by the Department based on their outstanding socioeconomic, recreational, ecological, or aesthetic values.

These stormwater permits impose basic requirements on the permitholder, including the preparation of a stormwater pollution prevention plan (SWPPP) describing the potential pollution sources and applicable pollution controls and measures, the implementation of best management practices (BMPs) for minimizing stormwater runoff, and the performance of regular pollutant sampling, monitoring, and reporting. Failure to comply with these requirements or to apply for a permit in the first place can subject unwitting persons to significant fines and penalties. The Clean Water Act allows citizen groups to bring a lawsuit to enforce the NPDES permitting requirements, with non-compliant persons on the hook for the costs of bringing an enforcement action, including the citizen group’s attorney fees.

In recent years, we have seen a significant uptick in the Attorney General’s Office utilizing this process to hold various industrial actors accountable for alleged permit violations. Frequently, these actors have been unaware of their obligations under the various stormwater permits. We have helped them navigate the process to resolution, typically through a negotiated consent decree. We have also advised clients on general permit compliance in order to avoid the risk of a citizen suit action or even in the context of a business transaction involving an industrial facility.

receive news & alerts

Yes, I’d like to receive updates with firm news and insights that are relevant to me.