City and County of San Francisco v. EPA (2025)

On March 4, 2025, the U.S. Supreme Court ruled in a 5-4 decision that the Environmental Protection Agency (EPA) had overstepped its statutory limits by imposing broad, outcome-based mandates on water discharge permits. The ruling limits the EPA’s authority to enforce general water quality requirements, instead requiring clear, enforceable pollution limits in permits.

The case of City and County of San Francisco v. Environmental Protection Agency centered on the federal government’s role in regulating water discharge permits. The EPA, the federal agency responsible for enforcing the Clean Water Act (CWA), oversees the National Pollutant Discharge Elimination System (NPDES), which regulates wastewater discharge. While the EPA has delegated permitting authority to 47 states, it retains oversight by reviewing programs, conducting audits, and ensuring compliance with federal standards.

San Francisco operates combined wastewater treatment facilities that process both wastewater and stormwater in the same infrastructure. During heavy rainfall, these systems risk becoming overwhelmed, leading to untreated discharges directly into the Pacific Ocean and San Francisco Bay. To mitigate this, historically, the city's NPDES permits included numerical and procedural discharge limits to ensure compliance with federal and state water quality standards. These permits specified the maximum allowable pollutant levels, treatment requirements, and operational procedures to minimize environmental and public health risks.

However, evolving regulatory approaches have sought to impose broader conditions beyond specific discharge limits, shifting toward outcome-based water quality requirements. In 2019, the EPA introduced new requirements for San Francisco’s NPDES permit, expanding its scope to include broad mandates. The revised permit required that the city:

1. Must not contribute to a violation of any water quality standard.

2. Must not create pollution, contamination, or nuisance as defined by state law.

San Francisco argued that these "end-result" requirements were overly vague and exceeded the EPA’s authority, as they imposed liability beyond the city's direct control. The city first challenged the decision in the Ninth Circuit Court of Appeals, which upheld the EPA’s authority. However, after an appeal, the U.S. Supreme Court ruled in favor of San Francisco. Justice Alito, writing for the Opinion of the Court, stated:

“This case involves provisions that do not spell out what a permittee must do or refrain from doing; rather, they make a permittee responsible for the quality of the water in the body of water into which the permittee discharges pollutants… For convenience, we will call such provisions ‘end-result’ requirements.”

Justice Barrett, in her dissenting opinion joined by the Democratic-appointed justices, argued that the majority's decision weakens the EPA’s ability to enforce water quality protections effectively, stating:

“The entire function of §1311(b)(1)(C) [Clean Water Act] is to ensure that permitted discharges do not violate state water quality standards… Conditions that forbid the city to violate water quality standards are plainly ‘limitations’ on the city’s license to discharge.”

The Supreme Court's ruling limits the EPA’s ability to impose broad, outcome-based mandates and requires it to establish clear conditions specifying direct pollution limits. This decision places greater responsibility on state agencies to regulate and enforce water quality standards while restricting federal intervention.

Implications of the Ruling

1. Limits EPA’s Power to Regulate Water Quality

1. The ruling prevents the EPA from issuing broad mandates on water quality and instead requires it to specify measurable pollution limits.

b. State agencies must now take the lead in enforcing strong water quality standards, but enforcement may be inconsistent across states due to differences in budget, capacity, and political will.

2. More Precise Permit Requirements for Polluters

1. The ruling requires the EPA and states to be explicit in permit writing and regulation.

b. This could allow for more targeted legal challenges rather than broad, difficult-to-prove claims about water quality violations.

c. If state agencies take the lead in crafting detailed, enforceable regulations, the public and advocacy groups can better track compliance and hold violators accountable.

3. Increased Reliance on State-Level Water Quality Protection

1. This ruling shifts greater enforcement discretion to states, requiring them to adopt and maintain stronger regulations to protect waterways, ecosystems, and public health.

Wastewater Permitting in Louisiana

In Louisiana, the Department of Environmental Quality (LDEQ) manages wastewater discharge permits through the Louisiana Pollutant Discharge Elimination System (LPDES). The quality and enforcement of these permits play a critical role in maintaining water quality standards across the state. The EPA delegated NPDES authority to Louisiana in 1996, making LDEQ responsible for issuing and enforcing water discharge permits. Currently, LDEQ administers permits for 1,220 individual facilities.

According to the EPA's 2022 Program and Permit Quality Review, LDEQ's public notice process aligns with federal requirements and provides opportunities for public engagement. However, the review also identified areas for improvement, including clearer documentation of water quality-based effluent limits, standardized monitoring requirements, and improved timeliness in permit issuance.

Key Aspects of Wastewater Permitting

• All states must regulate water discharges under NPDES standards set by the Clean Water Act.

• LDEQ issues both individual and general permits to regulate municipal and industrial discharges.

• Permits are renewed every five years.

• Facilities must regularly monitor their discharges and submit Discharge Monitoring Reports (DMRs).

• LDEQ has the authority to issue fines, modify permits, and pursue legal action against violators.

• Unlike some states, Louisiana’s enforcement approach is heavily influenced by regional water challenges, including coastal erosion and industrial activity.

Engaging in the public comment process is vital for ensuring that permits consider community concerns and environmental impacts. Submitting informed comments can influence permit conditions and enforcement actions. You can track current permits or join the mailing list for updates here: https://deq.louisiana.gov/page/lpdes 

Conclusion

The Supreme Court's decision in City and County of San Francisco v. Environmental Protection Agency (2025) fundamentally shifts the Clean Water Act permitting system by requiring clearer, more enforceable permits while weakening federal oversight. This change places greater responsibility on state agencies to adopt and maintain strong regulations to protect waterways, ecosystems, and public health.

However, the ruling raises concerns about permitting challenges. Gathering site-specific data for precise effluent limits can take years, and the EPA has historically used broad water quality mandates to prevent delays that could stall municipal projects and business developments. With these mandates struck down, regulators may face administrative hurdles in setting enforceable permit conditions, leading to slower approvals and greater compliance uncertainty for permittees.

Ultimately, the impact of this ruling will depend on how rigorously state agencies enforce permit conditions and whether additional federal legislative action addresses gaps in enforcement. Ensuring long-term water quality protections will require proactive state action, strengthened regulatory frameworks, and sustained advocacy at both state and federal levels.