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Clean Water Act

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Clean Water Act

The Clean Water Act (CWA) establishes the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. The basis of the CWA, the Federal Water Pollution Control Act was enacted in 1948, but the Act was significantly reorganized and expanded in 1972. "Clean Water Act" became the Act's common name with amendments in 1977.

Under the CWA, EPA has implemented pollution control programs such as setting wastewater standards for industry and water quality standards for all contaminants in surface waters.

The CWA made it unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained. EPA's National Pollutant Discharge Elimination System (NPDES) permit program controls discharges. Point sources are discrete conveyances such as pipes or man-made ditches. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. CWA regulations that impact the University include:

  • Links
  • Construction Activities – discusses the stormwater discharge requirements for construction sites >1 acre
  • Industrial Pretreatment Program – details the regulation of discharges that go directly to a Publicly Owned Treatment Works (POTW)

Stormwater Discharge Permits for Construction Activities

Stormwater runoff from construction activities can have a significant impact on water quality. As stormwater flows over a construction site, it can pick up pollutants such as  sediment, debris, and chemicals and transport these to a nearby storm sewer system or directly to a river, lake, or coastal water. Polluted stormwater runoff can harm or kill fish and other wildlife. Sedimentation can destroy aquatic habitat, and high volumes of runoff can cause stream bank erosion. Debris can clog waterways and potentially reach the ocean where it can kill marine wildlife and impact habitat.

The National Pollutant Discharge Elimination System (NPDES) stormwater program requires construction site operators engaged in clearing, grading, and excavating activities that disturb 1 acre or more, including smaller sites in a larger common plan of development or sale, to obtain coverage under a general NPDES permit for their stormwater discharges. Most states are authorized to implement the Stormwater NPDES permitting program.

Duke University’s  “Stormwater Management – Stormwater Discharges Associated with Construction Activity” Practice  outlines the following requirements that when implemented will assure compliance with the regulations:

  • Submittal of a Land Disturbance Permit Application with drawings to local and state authorities,
  • Implementation of approved permit conditions and Best Management Practices,
  • Management of site activities to reduce environmental impacts, and
  • Inspection frequency and reporting requirements to be compliant with the permit and other local, state, and federal requirements.

Industrial Pretreatment Program

Direct discharges to a publicly owned treatment works (POTW) are regulated under the CWA. The national pretreatment program (CWA Section 307(b)) controls the direct discharge of pollutants to POTWs by "industrial users." Facilities regulated under Section 307(b) must meet certain pretreatment standards. The goal of the pretreatment program is to protect municipal wastewater treatment plants from damage that may occur when hazardous, toxic, or other wastes are discharged into a sewer system and to protect the quality of sludge generated by these plants. Discharges to a POTW are regulated primarily by the POTW itself, rather than the state/tribe or EPA.

EPA has developed general pretreatment standards and technology-based standards for industrial users of POTWs in many industrial categories. Different standards may apply to existing and new sources within each category. "Categorical" pretreatment standards applicable to an industry on a nationwide basis are developed by EPA. In addition, other pretreatment standards, "local limits," are developed by the POTW to help the POTW achieve the effluent limitations in its NPDES permit.

Drain Disposal Practice

Duke University had developed a Drain Disposal Practice that establishes limitations regarding the disposal of chemicals through campus laboratory sinks or other systems or devices that drain into the local sewer system without treatment. Disposal limitations and allowances are based on federal clean water regulations, the Durham City Sewer Use Ordinance, and similar local ordinances or rules.

The Practice contains:


  • A description of classes of substances that are prohibited or restricted from being poured down a drain into a local sewer system. Drain disposal is prohibited even if these substances are diluted plus it is illegal to dilute a substance to avoid complying with these rules,
  • A description of the local wastewater treatment discharge standards and wastewater pretreatment pollutants that are prohibited, and
  • A description of acceptable chemicals that can be disposed of down the drain, providing the solution does not contain materials otherwise prohibited.