Stormwater Guide

May 1, 2011
Activities that take place at industrial facilities, such as material handling and storage, are often exposed to the weather.

EPA Guide to Stormwater Discharges from Industrial Facilities

Activities that take place at industrial facilities, such as material handling and storage, are often exposed to the weather. As runoff from rain or snowmelt comes into contact with these activities, it can pick up pollutants and transport them to a nearby storm sewer system or directly to a river, lake, or coastal water.

Stormwater detention systems can range from small basins to large underground complexes, like this system using 48-inch corrugated HDPE pipe under a parking lot.

To minimize the impact of stormwater discharges from industrial facilities, the National Pollutant Discharge Elimination System (NPDES) program includes an industrial stormwater permitting component that covers 10 categories of industrial activity that require authorization under an NPDES industrial stormwater permit for stormwater discharges.

All but five states are authorized to implement the Stormwater NPDES permitting program. Therefore, the vast majority of industrial facilities will need to obtain NPDES permit coverage through their state. For industrial facilities located in areas where EPA is the permitting authority, coverage is available under the Multi-Sector General Permit (MSGP).

EPA maintains a website at that includes a variety of tools and information resources for industrial stormwater dischargers.

Key offerings include:
The Industrial Stormwater Permit Guide -This tool explains the federal stormwater regulations for businesses

Trash rakes, like this system from Duperon, can help remove larger debris from stormwater runoff.

and the permitting and waiver options available. The site also includes a photo gallery with discussion of 16 different types of stormwater control measures documenting compliant and non-compliant situations.

Water Locator Tool - This tool is designed to help facilities complete a Notice of Intent (NOI) by locating receiving waters and determining whether that waterbody is considered "impaired" under Section 303(d) of the Clean Water Act.

Industrial Sector Fact Sheets - EPA developed individual fact sheets for each of the 29 industrial sectors. Each sector fact sheet summarizes the type of facilities included in that sector, the pollutants associated with the sector, and the type of stormwater control measures used to minimize the discharge of those pollutants.

Conditional "No Exposure" Exclusion - If an industrial facility can certify that its industrial materials and operations are not exposed to stormwater, it is excluded from NPDES industrial stormwater permit requirements provided that the operator notifies the permitting authority at least every five years.

Industrial Stormwater Pollution Prevention Plan (SWPPP) Guidance - Provides guidance on developing a SWPPP that meets the requirements of the 2008 MSGP.

Search, Sort, and View Industrial NOIs - Searchable database of stormwater notices of intent (NOIs) for industrial facilities seeking coverage under EPA's MSGP.

New Permit Targets Construction Stormwater Discharges

The U.S. Environmental Protection Agency has issued a proposed new National Pollutant Discharge Elimination System (NPDES) general permit for stormwater discharges from construction activities.

Construction sites disturbing one or more acres of land or smaller sites that are part of a common plan of development or sale are required to obtain NPDES permit coverage for their stormwater discharges. Since 1992, EPA has issued a series of Construction General Permits (CGPs) that provide permit coverage in states where EPA is the permitting authority. At present, EPA is the permitting authority in four states (Idaho, Massachusetts, New Hampshire, and New Mexico); the District of Columbia; Puerto Rico; and all other U.S. territories, with the exception of the U.S. Virgin Islands.

The current 2008 CGP is set to expire on June 30, 2011. EPA has proposed to extend the permit until January 31, 2012, to provide the agency with sufficient time to finalize the new permit.

The new general permit will provide coverage for eligible new and existing construction projects for a period of five years. It will include a number of modifications from its predecessor, many of which are necessary to implement the new Effluent Limitations Guidelines (ELGs) for the Construction and Development (C&D) point source category.

Effluent Limitations

EPA finalized the Effluent Limitations Guidelines and New Source Performance Standards for the construction and development industry on December 1, 2009. The C&D rule became effective on February 1, 2010; after which all NPDES construction stormwater permits are required to incorporate the C&D rule requirements once their current permit expires.

The requirements in the C&D rule include a suite of non-numeric effluent limitations that apply to all permitted construction sites (see 40 CFR 450.21.) The non-numeric effluent limits include requirements for:

  • Erosion and Sediment Controls
  • Soil Stabilization
  • Dewatering
  • Pollution Prevention Measures
  • Prohibited Discharges
  • Surface Outlets

The C&D rule also included a numeric limit for turbidity. However, EPA discovered after promulgation that the data used to calculate the numeric limit was misinterpreted. The agency has issued a stay for the numeric limit for turbidity so that the limit can be recalculated.

EPA's proposed CGP includes language that implements the C&D rule's non-numeric limits and includes a placeholder for the recalculated numeric turbidity limit. It also includes corresponding permit requirements for monitoring, reporting, and the acreage threshold. If EPA promulgates a recalculated numeric turbidity limit before the new CGP is finalized, the agency plans to include the revised limit and associated monitoring requirements in the finalized CGP.

CGP Summary

The proposed CGP includes a number of new provisions relating not only to the C&D rule effluent limits, but also to provide enhanced protections for impaired or other sensitive waters. In addition, the proposed permit has been modified from the existing 2008 permit to improve its readability, clarity, and enforceability. Some of the significant permit modifications in the proposed CGP include new requirements for:

  • Eligibility for emergency-related construction
  • Required use of the electronic Notice of Intent process
  • Sediment and erosion controls
  • Natural buffers or alternative controls
  • Soil stabilization
  • Pollution prevention
  • Site inspections
  • Stormwater Pollution Prevention Plans
  • Permit termination
How to Comment

EPA will accept comment on the proposed permit until mid-June. For additional information on the CGP or to view or download the complete text of the Federal Register notice, please visit:

Simple Stormwater BMP Options for the Paper Industry

The Environmental Protection Agency has developed individual fact sheets for each of the 29 industrial sectors subject to stormwater permits. As one example, a variety of BMP options may be applicable to eliminate or minimize the presence of pollutants in stormwater discharges from paper and allied product manufacturing facilities. The following are EPA's suggested BMPs for that sector.

Good Housekeeping Practices

Good housekeeping includes establishing protocols to reduce the possibility of mishandling materials or equipment and training employees in good housekeeping techniques. Common areas where good housekeeping practices should be followed include trash containers and adjacent areas, material storage areas, vehicle and equipment maintenance areas, and loading docks.

Good housekeeping practices must include a schedule for regular pickup and disposal of garbage and waste materials and routine inspections of drums, tanks, and containers for leaks and structural conditions. Practices also include containing and covering garbage, waste materials, and debris. Involving employees in routine monitoring of housekeeping practices has proven to be an effective means of ensuring the continued implementation of these measures.

Minimizing Exposure

Where feasible, minimizing exposure of potential pollutant sources to precipitation is an important control option. Minimizing exposure prevents pollutants, including debris, from coming into contact with precipitation and can reduce the need for BMPs to treat contaminated stormwater runoff. It can also prevent debris from being picked up by stormwater and carried into drains and surface waters. Examples of BMPs for exposure minimization include covering materials or activities with temporary structures (e.g., tarps) when wet weather is expected or moving materials or activities to existing or new permanent structures (e.g., buildings, silos, sheds). Even the simple practice of keeping a dumpster lid closed can be a very effective pollution prevention measure.

Erosion and Sediment Control

BMPs must be selected and implemented to limit erosion on areas of a site that, due to topography, activities, soils, cover, materials, or other factors are likely to experience erosion. Erosion control BMPs such as seeding, mulching, and sodding prevent soil from becoming dislodged and should be considered first. Sediment control BMPs such as silt fences, sediment ponds, and stabilized entrances trap sediment after it has eroded. Sediment control BMPs should be used to back-up erosion control BMPs.

Management of Runoff

A stormwater pollution prevention plan (SWPPP) must contain a narrative evaluation of the appropriateness of stormwater management practices that divert, infiltrate, reuse, or otherwise manage stormwater runoff so as to reduce the discharge of pollutants. Appropriate measures are highly site-specific, but may include, among others, vegetative swales, collection and reuse of stormwater, inlet controls, snow management, infiltration devices, and wet retention measures.

EPA's Fact Sheets covering the 29 industrial sectors subject to stormwater permits may be found at

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