RIPDES Stormwater Industrial Activity

Background and Regulatory Authority

On November 16, 1990, EPA issued the National Pollutant Discharge Elimination System (NPDES) Phase I stormwater regulations that required owners or operators of specific categories of industrial facilities, which discharge stormwater directly to the waters of the United States or indirectly through a separate storm sewer system via a point source conveyance, to obtain a NPDES stormwater permit.

Rhode Island has been delegated by EPA and is authorized to issue individual or general permits under the Rhode Island Pollutant Discharge Elimination System (RIPDES) Program to cover discharges of industrial stormwater. In 1993, the RIPDES Program developed a statewide baseline general permit to cover all stormwater discharges associated with industrial activity, excluding discharges from construction sites. RIPDES re-issued this permit in 1998 and 2003. In 2006, the RIPDES Program issued the first Rhode Island Multi-Sector General Permit (MSGP) to cover stormwater discharges associated with Industrial Activity. The MSGP was re-issued in 2013 and on May 3, 2019.

Who Needs a RIPDES Industrial Stormwater Permit?

Owners or operators of specific categories of industrial facilities, which discharge stormwater directly to the waters of the State or indirectly through a separate storm sewer system via a point source conveyance, are required to obtain authorization of their discharges under the RIPDES MSGP. Ten major categories of industrial activities have been designated as requiring permit coverage. In general, the 10 categories of industrial activities are as follows:

  • Category One (i): Facilities subject to federal stormwater effluent discharge standards in 40 CFR Parts 405-471
  • Category Two (ii): Heavy manufacturing (for example, paper mills, chemical plants, pretroleum refineries, and steel mills and foundries)
  • Category Three (iii): Coal and mineral mining and oil and gas exploration and processing
  • Category Four (iv): Hazardous waste treatment, storage, or disposal facilities
  • Category Five (v): Landfills, land application sites, and open dumps with industrial wastes
  • Category Six (vi): Metal scrapyards, salvage yards, automobile junkyards, and battery reclaimers
  • Category Seven (vii): Steam electric power generating plants
  • Category Eight (viii): Transportation facilities that have vehicle maintenance, equipment cleaning, or airport deicing operations
  • Category Nine (ix): Treatment works treating domestic sewage with a design flow of 1 million gallons a day or more
  • Category Eleven (xi): Light manufacturing (For example, food processing, printing and publishing, electronic and other electrical equipment manufacturing, and public warehousing and storage)

Permitting Options

Owners and operators of regulated industrial facilities have the following options to obtain permit coverage or be exempted from permit requirements if the industrial stormwater operations are not exposed to stormwater:

  • A. General Permit (Multi-Sector General Permit)- The 2019 Rhode Island Multi-Sector General Permit for Stormwater Discharge Associated with Industrial Activity prescribes one set of requirements for groups/sectors of Permittees. The Best Management Practices used to meet the requirements of the permit can be tailored to the specific conditions of the facility. A Notice of Intent (NOI) serves as the application for the General Permit. The operator must electronically submit the NOI and Storm Water Management Plan using EPA's NeT. Note: Industrial stormwater discharges owned or operated by municipalities are also eligible for permit coverage under the General Permit for Small MS4s and Industrial Activity at eligible facilities operated by regulated Small MS4s.
  • B. Individual Permit - The Individual Permit provides the owner/operator of a regulated facility with the opportunity of seeking coverage with a Stormwater Management Plan tailored to their needs.
  • C. Conditional "No Exposure" Certification - Industrial facilities can certify that their industrial materials and operations are not exposed to stormwater, these facilities are excluded from RIPDES industrial stormwater permit requirements provided that the operator submits electronically a "No Exposure Certification" Exclusion.
  • D. "No Discharge Certification" – Industrial facilities generating storm water associated with industrial activities that is not discharged to waters of the State are not required to obtain permit coverage. Facilities which are not required to be permitted must either be: (1) engineered and constructed to contain all storm water associated with industrial activities from discharging to waters of the State, (2) located in basins or other physical locations that are not hydrologically connected to waters of the State, or (3) have all stormwater associated with industrial activity discharged via Combined Sewer Systems. Facilities claiming No Discharge may submit electronically a "No Discharge Certification"

For more information, email Elliot Anderson at

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