Regulatory Library

Clean Water Act (CWA)


The basic framework for the current national water quality programs was put in place by Congress with the Federal Water Pollution Control Act (FWPCA) of 1972 and the Marine Protection, Research and Sanctuaries Act (MPRSA) of 1972. The Clean Water Act (CWA) of 1977 reorganized the FWPCA and added a major new program to control toxic water pollutants. Of the subsequent amendments to these statutes, the most significant are the Water Quality Act of 1987 which addressed "toxic hot spots" and storm water discharges, and the Oil Pollution Act of 1990, which tightened controls on discharges of oil and hazardous substances.   In many states, State Environmental Requirements go above and beyond the federal CWA requirements.

The primary purpose of the CWA is to restore and protect the quality of the nation’s surface waters.  As originally approved, the ultimate goal of the Act was to eliminate the discharge of pollutants into navigable waters, with an interim goal of insuring waters were "fishable and swimable".  Although the ultimate goal has become less emphasized over time, there is still a clear statement that it is unlawful to discharge pollutants into waterways except as provided by the terms of the Act.  The surface waters covered by the Act are defined quite broadly, and include rivers, lakes, intermittent streams, and even wetlands.  (However, the definition does not extend to ground water, which is covered by the Safe Drinking Water Act.)

Pollutants regulated under the CWA include "conventional" pollutants, such as biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform, oil and grease, and pH; "priority" pollutants, such as various toxic pollutants; and "non-conventional" pollutants which are pollutants not identified as either conventional or priority.

Five major types of CWA requirements that affect the chemical industry are:
  • "point source" direct discharge limitations
  • pre-treatment requirements for indirect discharges
  • storm water standards
  • oil and hazardous substances spill prevention and response
  • wetlands modification &/or dredge and fill
Direct Discharges

Direct discharges from "point sources" into "waters of the United States" are addressed by the National Pollutant Discharge Elimination System (NPDES) permitting program.  "Point sources" include pipes, sewers, and even drainage ditches; that is, any contained flow of wastewater.  "Waters of the United States" is defined quite broadly to include surface waters such as rivers, lakes, intermittent streams, and even wetlands.

NPDES permits are issued either directly by EPA or by an authorized state. A facility that intends to discharge into the nation’s waters must obtain a permit prior to initiating its discharge. A permit applicant must provide quantitative analytical data identifying the types of pollutants present in the facility’s effluent. The permit will then set fourth the conditions and effluent limitations under which a facility may make a discharge.

NPDES discharge limits are either technology based, based on federal or state water quality criteria, or a combination of both. Technology-based point source discharge limits have been established by EPA regulations under the effluent guidelines program. Limits are, in some cases, industry specific. Federal or State water quality criteria or standards designed to protect designated uses of surface waters, such as supporting aquatic life or recreation, generally do not take into account technological feasibility or costs. Water quality criteria and standards vary from state to state, and from site to site, depending on the use classification of the receiving body of water. Most states follow EPA guidelines, which propose aquatic life and human health criteria for many of the 126 priority pollutants.

Indirect Discharges

Indirect discharges to publicly-owned treatment works (POTWs, also known as municipal wastewater treatment plants or sewage treatment plants) must meet pre-treatment requirements. National pretreatment standards can be found in 40 CFR 403 General Pretreatment Regulations for Existing and New Sources of Pollution at Section 403.6 National Pre-Treatment Standards: Categorical Standards. Under this program, individual POTWs may establish industrial pre-treatment permit requirements as necessary to achieve their own effluent limitations.

Direct and Indirect Discharges Specific to the Chemical Industry

NPDES Effluent guidelines and pre-treatment standards by industry:
  • 40 CFR 414 Organic Chemicals, Plastics, and Synthetic Fibers
  • 40 CFR 415 Inorganic Chemicals Manufacturing
  • 40 CFR 417 Soap and Detergent Manufacturing
  • 40 CFR 418 Fertilizer Manufacturing
  • 40 CFR 422 Phosphate Manufacturing
  • 40 CFR 428 Rubber Manufacturing
  • 40 CFR 446 Paint Formulation
  • 40 CFR 447 Ink Formulation
  • 40 CFR 454 Gum and Wood Chemicals Manufacturing
  • 40 CFR 455 Pesticide Chemicals
  • 40 CFR 457 Explosives Manufacturing
  • 40 CFR 458 Carbon Black Manufacturing
Storm Water Runoff

The 1987 amendments of the CWA required EPA to develop requirements to address storm water runoff from industrial sites. Storm water discharge associated with industrial activity means the discharge from any conveyance which is used for collecting and conveying storm water and which is directly related to manufacturing, processing or raw material storage areas at an industrial plant (40 CFR 122.26 (b)(14)). These regulations require that facilities with the following storm water discharges apply for an NPDES permit: (1) a discharge associated with industrial activity; (2) a discharge from a large or medium municipal storm sewer system; or (3) a discharge which EPA or the State determines to contribute to a violation of a water quality standard or is a significant contributor of pollutants to waters of the United States. These regulations can be found in 40 CFR 122 The National Pollution Discharge Elimination System at Section 122.26 Storm Water Discharges.

The Storm Water Rule (40 CFR 122.26(b)(14) Subparts (i, ii)) requires the capture and treatment of storm water at facilities producing chemicals and allied products, including industrial organic chemical manufacture. Required treatment will remove from storm water flows a large fraction of both conventional pollutants, such as suspended solids and biological oxygen demand (BOD), as well as toxic pollutants, such as certain metals and organic compounds.

Oil and Hazardous Substance Spill Prevention and Response

The CWA has various provisions to prevent and manage spills of hazardous substances that might affect waterways. Most of these provisions have been incorporated into the regulations of the emergency response laws (CERCLA and EPCRA). However, one specific requirement here is the Spill Prevention, Control and Countermeasure (SPCC) plan, which is required for any facility that has oil or hazardous materials storage with the potential for releases into waterways.

The Oil Pollution Act of 1990 significantly expanded requirements to develop Spill Prevention, Control and Countermeasure (SPCC) plans. Previously, SPCC plans were only required for facilities that stored oil above fairly large threshold amounts. The expanded requirement applies to any oil or hazardous materials storage at industrial facilities with the potential for releases to reach navigable waters. The full text of these regulations can be found in 40 CFR 112 Oil Pollution Prevention.

Wetlands Modification &/or Dredge and Fill

Under the CWA, the placement of dredge and fill materials into surface waters is exempted from NPDES coverage, and  is covered instead by a permit program administered by the Army Corps of Engineers (COE).   As mentioned above, the CWA defines surface waters to include wetlands, thus activities that involve the modification of wetlands are also generally covered by the COE permit program.  The standards for this permit program are found in Section 404 of the CWA.

It should be noted that a number of  states also have specific requirements affecting the use of wetlands. 

EPA’s Office of Water, at (202) 260-5700, will direct callers with questions about the CWA to the appropriate EPA office. EPA also maintains a bibliographic database of Office of Water publications which can be accessed through the Ground Water and Drinking Water resource center, at (202) 260-7786.

Program office links:
Office of Water

40 CFR 414- 458  NPDES Effluent guidelines and pre-treatment standards by industry

40 CFR 403 General Pretreatment Regulations for Existing and New Sources of Pollution Categorical national pretreatment standards

40 CFR 122 The National Pollution Discharge Elimination System Stormwater runoff regulations

40 CFR 112 Oil Pollution Prevention  SPCC regulations

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