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Cooling Water Intakes

  • Cooling water intake and fish screen
  • Examples of cooling towers

Thousands of industrial facilities use large volumes of water from lakes, rivers, estuaries or oceans to cool their plants.

Cooling water intake structures cause adverse environmental impact by pulling large numbers of fish and shellfish or their eggs into a power plant's or factory's cooling system.
  • Organisms may be killed or injured by heat, physical stress, or by chemicals used to clean the cooling system.
  • Larger organisms may be killed or injured when they are trapped against screens at the front of an intake structure.

Section 316(b) of the Clean Water Act requires EPA to issue regulations on the design and operation of intake structures, in order to minimize adverse impacts. 

Regulated Facilities

Regulated facilities have NPDES permits and are designed to withdraw at least 2 million gallons per day from waters of the U.S.
 
Many industrial sectors are affected. The sectors with the largest number of regulated facilities are:
  • Electric generating plants
  • Pulp and paper mills
  • Chemical manufacturing plants
  • Iron and steel manufacturing
  • Petroleum refineries
  • Food processing
  • Aluminum manufacturing
For precise definitions of coverage, see the regulations at 40 CFR 125.81, 125.91 and 125.131.
  • NPDES industrial permit information

Regulations

The cooling water intake requirements are included in the NPDES permit regulations, 40 CFR Parts 122 & 125 (Subparts I, J, & N).

2014 - Existing Electric Generating Plants and Factories
  • Final Rule - Federal Register Notice (August 15, 2014)
  • Summary & support documents
Rulemaking History
  • 2001-2006 regulations (New facilities)
Implementation Support
  • Facility lists
  • Information on threatened and endangered species
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on June 16, 2022
United States Environmental Protection Agency

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