Supreme Court Limits Clean Water Act

The Clean Water Act (CWA) gives the U.S. Environmental Protection Agency (U.S. EPA) the authority to impose requirements on facilities that wish to discharge “pollutants” into the waters of the United States. These requirements are in the form of National Pollutant Discharge Elimination System (NPDES) Permits and consist of requirements including effluent limits, sampling requirements, pollution prevention plans, and more. On October 16, 2024 the Supreme Court argued the authority of NPDES permits to prescribe “end-result” requirements, which “do not spell out what a permittee must do or refrain from doing but instead make a permittee responsible for the quality of the water in the body of water into which the permittee discharges.”

March 2025 Ruling

On March 5^th, 2025 the Supreme Court ruled in a 5-4 decision that the CWA does not have authority to impose narrative “end result” requirements referencing effect on the quality of the waters that receive it rather than the nature of the discharge itself, and it is the U.S. EPA’s responsibility and expertise to determine what limits discharging facilities must meet. The case at hand for this decision involved the City of San Francisco’s Combined Sewer Overflow (CSO) NPDES permit, which prohibits discharges that “cause or contribute to a violation of any applicable water quality standard.”

The dissenting justices argued that since the CWA allows U.S. EPA to impose “any more stringent limitation that is necessary to meet . . . or required to implement any applicable water quality standard” that any requirement based on the receiving water body is plainly just a limitation on discharge.

The final 5-4 ruling will restrict U.S. EPA’s ability to create limitation in NPDES Permits based on receiving body and will put the burden on U.S. EPA to determine what facility specific limitation would need to be met.

What This Means

U.S. EPA will be forced to remove “end-result” requirements from their NPDES Permits but could impose other requirements which would compensate for this loss. This could include more stringent effluent discharge limits, or more frequent testing and reporting requirements.

The following states and territories have not been granted NPDES permitting authority, meaning the U.S. EPA directly administers NPDES permits in these states, and therefore is directly affected by U.S. EPA issued NPDES permits.

• Massachusetts
• New Hampshire
• New Mexico
• District of Columbia

While the other 47 states must still comply with the Supreme Court’s ruling of the CWA, since each state issues its own NPDES permits the language, methods, and requirements in each state NPDES permits will differ.

What Can You Do?

Keep an eye out for newly issued NPDES from the U.S. EPA or your facility’s governing state agency. If you want to discuss your facilities permitting NPDES strategy ALL4 is ready to help, please reach out to Evan Mia at emia@all4inc.com.