Official websites use .gov
A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS
A lock (Lock A locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Cooling Water Intakes

slide 1 of 2 * ## Cooling Water Intake Screens Section 316(b) of the Clean Water Act requires the EPA to issue regulations on the location, design and operation of cooling water intake structures, in order to minimize adverse environmental impacts. Explore rulemaking history * ## Implementation Materials for Regulators The EPA provides implementation materials to support permit writers, affected facilities and other interested stakeholders. Access regulatory support documents * ## Cooling Water Intake Screens Section 316(b) of the Clean Water Act requires the EPA to issue regulations on the location, design and operation of cooling water intake structures, in order to minimize adverse environmental impacts. Explore rulemaking history * ## Implementation Materials for Regulators The EPA provides implementation materials to support permit writers, affected facilities and other interested stakeholders. Access regulatory support documents

12

Cooling water intake structures cause adverse environmental impacts

Intake structures pull large numbers of fish and shellfish or their eggs into a power plant's or factory's cooling system. Thousands of industrial facilities use large volumes of water from lakes, rivers, estuaries or oceans to cool their plants. 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.

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 125.81Exit EPA’s Website, 125.91Exit EPA’s Website and 125.131Exit EPA’s Website. * 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 NoticeExit EPA’s Website (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 about Cooling Water Intakes to ask a question, provide feedback, or report a problem. Last updated on April 7, 2026 Welcome! Please share your feedback on how we can make www.epa.gov work better for you. A red asterisk (*) indicates a required field.

Success

Thank you. Your feedback has been received.

Error

alert message Required Questions - page 1 of 2 question_55203_answer_01 How would you rate your experience on www.epa.gov today? *

0 Stars 1 Star 2 Stars 3 Stars 4 Stars 5 Stars Please explain the reason for your rating. * 400 characters allowed Would you like to take two more minutes to answer more questions to help us improve our services? Yes, keep going → No, only submit these responses Optional questions - page 2 of 2 How would you describe yourself? Business Government employee Scientist Student Other Enter other text Please tell us why you visited www.epa.gov today. 400 characters allowed Did you visit www.epa.gov to accomplish a specific task? If yes, please explain why you were able or unable to accomplish your task. 400 characters allowed How can we make www.epa.gov a more helpful website? 400 characters allowed Submit [NPDES]: National Pollutant Discharge Elimination System [*]: required