Stormwater Regulatory Overview

The Federal Water Pollution Control Act, more commonly called the Clean Water Act, prohibits the discharge of pollutants from a point source to waters of the United States without a National Pollution Discharge Elimination System (NPDES) permit. In 1990 the U.S. Environmental Protection Agency (EPA) specifically applied the NPDES permit requirement to stormwater discharges from 11 industrial sectors.  There are two types of NPDES permits: general and individual.  A general permit imposes nearly identical requirements on permit holders and the application process is nearly automatic.

The EPA has delegated permitting authority to most states, thus EPA only issues NPDES permits in states that do not have authority to administer the NPDES program (Massachusetts, New Hampshire and New Mexico). EPA regulates industrial stormwater discharges under its Multi-Sector General Permit (MSGP).  Many states similarly permit industrial stormwater under one general permit, though some states issue industry sector-specific general permits.  Industrial facilities rarely apply for individual permits for stormwater discharges, but the permitting authority may elect to transfer a facility to an individual permit to increase regulatory oversight.

While the specific components of general permits vary from state to state, there are some important common features.  General industrial permits require the facility owner or operator submit and implement a Stormwater Pollution Prevention Plan (SWPPP) that describes operational, structural and treatment best management practices (BMPs) that minimize stormwater pollution.  Many industrial permits also set forth numeric “benchmark” water quality concentrations to help facilities measure their BMPs’ efficacy, and require facilities to monitor and report effluent pollutant concentrations.  While benchmarks are not enforceable effluent limits, some permits do require active responses to benchmark excursions.  EPA has established additional enforceable, technology-based effluent limitations for stormwater associated with certain industrial activities.

Categories of Industrial Activity that Require Permit Coverage

The federal regulations, in 40 CFR 122.26(b)(14)(i)-(xi), identify 11 categories of stormwater discharges associated with industrial activity required to be covered under an NPDES permit (unless otherwise excluded). One category, Category 10, is construction sites that disturb five acres or more; however, because of the significant difference in the nature of those activities, construction sites are permitted separately.

EPA has issued a Multi-Sector General Permit (MSGP) that addresses stormwater discharges from 29 sectors of industrial activity. The 29 sectors are defined by either the facility’s Standard Industrial Classification (SIC) code or a general description of the facility’s industrial activities. The North American Industry Classification System (NAICS) will eventually replace the SIC system. The U.S. Census Bureau has a conversion table to bridge the two systems. For more information on each of the 29 sectors, view the Industrial Fact Sheet Series for Activities Covered by EPA’s MSGP.

More information about permitting stormwater discharges from construction activities is available. In general, the 10 categories of industrial activities are as follows:

(i): Facilities subject to federal stormwater effluent discharge standards in 40 CFR Parts 405-471

(ii): Heavy manufacturing (for example, paper mills, chemical plants, petroleum refineries, and steel mills and foundries)

(iii): Coal and mineral mining and oil and gas exploration and processing

(iv): Hazardous waste treatment, storage, or disposal facilities

(v): Landfills, land application sites, and open dumps with industrial wastes

(vi): Metal scrapyards, salvage yards, automobile junkyards, and battery reclaimers

(vii): Steam electric power generating plants

(viii): Transportation facilities that have vehicle maintenance, equipment cleaning, or airport deicing operations

(ix): Treatment works treating domestic sewage with a design flow of 1 million gallons a day or more

(xi): Light manufacturing (For example, food processing, printing and publishing, electronic and other electrical equipment manufacturing, and public warehousing and storage).

Stormwater Aquip Seaview
Solid Waste - Aquip sanitary
Metal Products - Aquip Emerald

This information is not intended to substitute for professional legal advice.