by Elias Aidun, Associate Member, University of Cincinnati Law Review Vol. 93
I. Introduction
In 1969, the Cuyahoga River in Cleveland Ohio caught fire—an event so shocking that it became a symbol of the nation’s unchecked industrial pollution.[1] Decades of wastewater dumping had turned the river into a flammable disaster, sparking national outrage and fueling the environmental movement of the 1970s.[2] In response, Congress significantly reorganized and expanded the Clean Water Act (“CWA”) in 1972, establishing sweeping federal protections for the nation’s waterways.[3] The goal was simple: to eliminate pollution and restore the health of America’s rivers, lakes, and oceans.
To enforce these protections, the CWA gave regulatory authority to the Environmental Protection Agency (“EPA”) and created the National Pollutant Discharge Elimination System (“NPDES”) permit program.[4] This program ensures that industries, cities, and other entities adhere to water quality standards before releasing wastewater into public waterways.[5] Specifically, the NPDES makes it unlawful to discharge pollutants into protected bodies of water unless authorized by permit.[6] For years, the EPA has maintained this authority to impose permit conditions, requiring compliance with pollution limits and environmental safeguards.[7] However, as environmental regulations have expanded, so too have the legal battles over how much power the EPA should have in enforcing them.
A recent Supreme Court ruling has put the limits of that authority to the test. On March 4, 2025, the Court ruled 5-4 in City and County of San Francisco v. Environmental Protection Agency, curbing the EPA’s ability to impose “end-result” water quality requirements in NPDES permits.[8] The case arose from a dispute over San Francisco’s wastewater treatment facility, where the EPA had mandated compliance with broad water quality standards, without specifying how the city should achieve them.[9] The Court’s decision held that such requirements exceeded the EPA’s statutory authority under the CWA, fundamentally altering how the agency can enforce water quality regulations moving forward.[10]
This article will explore the potential impact that City and County of San Francisco v. Environmental Protection Agency will have on the future of the EPA’s authority to regulate waterways under the CWA. Part II provides background on the CWA and the role of the EPA, as well as San Francisco’s challenge and the Supreme Court’s ruling. Part III discusses the Supreme Court’s rationale and implications for future regulatory actions. Finally, Part IV offers a brief conclusion of potential next steps for environmental advocates, lawmakers, and regulatory agencies.
II. Background
The CWA, originally enacted as the Federal Water Pollution Control Act of 1948 and significantly amended in 1972, is the primary federal law governing water pollution in the United States.[11] The Act was a direct response to growing environmental concerns, spurred by events such as the infamous Cuyahoga River fire, which underscored the desperate need for stronger water regulations.[12] Through the CWA, Congress set ambitious goals to eliminate pollutant discharges into navigable water and to restore and maintain the chemical, physical, and biological integrity of all U.S. waters.[13]
To achieve these goals, the CWA established the NPDES, a permit-based framework to regulate point source pollution.[14] The term “point source” is defined very broadly in the CWA, but twenty-five years of litigation have defined it as any discharge from discernible sources like a pipe, channel, or tunnel.[15] Similarly, the term “pollutant” is broadly defined in the CWA and includes any type of industrial, municipal, and agricultural waste discharged into the water.[16] Under the NPDES program, entities must obtain a permit before releasing pollutants into bodies of water, with permits containing limits on what you can discharge, monitoring and reporting requirements, and other provisions to ensure that the discharge does not hurt water quality or people’s health.[17] Essentially, the NPDES permit translates the general requirements of the CWA into specific provisions tailored to the operations of each entity discharging pollutants.[18]
Under the NPDES framework, permit holders must comply with specific effluent limits to control water pollution. These limits fall into two main categories: Technology-based Effluent Limitations (“TBEL”) and Water Quality-based Effluent Limitations (“WQBEL”).[19] TBELs in permits require a minimum level of treatment of pollutants for point source discharges based on available treatment technologies.[20] TBELs set baseline restrictions on pollutant discharges.[21] However, when TBELs alone are insufficient to protect water quality, the CWA and NPDES regulations require that the permit writer also impose WQBELs, which are stricter limitations tailored to meet the needs of a specific water body.[22] In essence, TBELs are intended to result in zero discharge of pollutants, while WQBELs are intended to change the quality of the body of water so that it supports the designated use.[23]
Over the years, the EPA has interpreted its regulatory authority broadly, requiring permit holders to not only comply with specific effluent limits but also to meet certain “end-result” water quality standards.[24] This means that the overall health of a water body, rather than just the contents of a discharge, must meet regulatory thresholds. This interpretation has frequently been challenged in court, particularly by municipalities and industries that argue the EPA is overstepping its statutory mandate under the CWA.[25]
A. Legal Battles Over the EPA’s Authority
The scope of the EPA’s authority to enforce the CWA has been the subject of intense litigation for decades, with courts often determining the boundaries of the agency’s regulatory power. Notably, the Supreme Court has ruled on several key cases that have shaped the interpretation of the CWA. For example, in Rapanos v. United States, the Court limited the definition of “waters of the United States,” narrowing the scope of water bodies subject to regulation.[26] Similarly, in Sackett v. EPA, the Court further restricted the EPA’s ability to regulate wetlands under the CWA.[27] These rulings reflect a broader judicial trend of curbing EPA’s power, particularly when regulatory actions are interpreted as exceeding congressional intent.
It is within this legal landscape that City and County of San Francisco v. EPA emerged. The dispute in the case arose from the EPA’s attempt to enforce broad water quality requirements on San Francisco’s Oceanside wastewater treatment facility.[28] The city operates two combined sewer systems, one discharging into San Francisco Bay and the other into the Pacific Ocean.[29] During heavy rainfall, the Oceanside facility occasionally overflows, releasing untreated wastewater, including raw sewage, into the ocean.[30]
In 2019, as part of the facility’s NPDES permit renewal, the EPA included two end-result conditions.[31] The first of these prohibits the facility from making any discharge that “contributes to a violation of any applicable water quality standard” for receiving waters.[32] The second provides that the City cannot perform any treatment or make any discharge that “creates pollution, contamination, or nuisance as defined by California Water Code section 13050.”[33] San Francisco challenged these provisions, arguing that they were overly vague and placed an undue burden on the city by making it liable for water quality standard violations beyond its direct control.[34] The City further contended that it could be heavily penalized even though it was never put on notice that it was obligated to take any specific step other than those it undertook.[35]
The case escalated through administrative and judicial review. The EPA’s Environmental Appeals Board denied San Francisco’s administrative appeal, and the U.S. Court of Appeals for the United States Court of Appeals for the Ninth Circuit denied San Francisco’s petition for review, holding that the CWA authorizes the EPA to include the challenged provisions in the Oceanside NPDES permit.[36] A divided panel of the Ninth Circuit deferred to the agency’s interpretation of Section 301(b)(1)(C) of the CWA, which authorizes the imposition of “any” limitations necessary to achieve water quality standards.[37] However, the Supreme Court ultimately reversed this decision, ruling that the EPA’s broad interpretation exceeded its statutory authority under the CWA.[38] Writing for the majority, Justice Samuel Alito interpreted Section 301(b)(1)(C), which authorizes “any more stringent limitation” necessary to meet water quality standards, concluding that this provision requires the EPA to include specific, quantifiable effluent limitations rather than open-ended directives tied to water quality.[39] This decision marks a significant shift in the agency’s regulatory reach, with potentially far-reaching consequences for future water quality enforcement.
III. Discussion
The Supreme Court’s decision in City and County of San Francisco v. EPA has sparked significant debate over the balance between regulatory clarity and the protection of water quality. While the ruling has provided clearer guidelines for regulated entities, it has also raised concerns about its potential to weaken the CWA’s ability to protect waterways.[40] The decision shifts the regulatory landscape, requiring the EPA to implement more specific, quantifiable standards in NPDES permits.[41] This change has led to differing perspectives from both industry groups and environmental advocates, each interpreting the ruling’s impact from their perspective.
A. Industry Groups: More Clarity
From the perspective of industry groups and municipal authorities, the Supreme Court’s ruling is viewed as a victory for regulatory certainty and clarity.[42] Before the decision, the EPA could impose vague, outcome-based conditions in permits, which often left regulated entities unsure about their compliance obligations and exposed them to the risk of penalties for violations that were difficult to predict or control.[43] By requiring more specific and quantifiable standards, the ruling offers a more predictable regulatory framework for industry groups and municipal authorities.[44] This clarity is seen as reducing the compliance risks for businesses and municipalities, as they will now know exactly what steps they must take to avoid violations.[45]
Industry groups, including those in sectors like wastewater treatment and manufacturing, argue that this shift will help prevent excessive regulatory exposure.[46] Instead of having to meet broad, ambiguous requirements, entities will now be able to implement concrete measures and technologies that are specifically tailored to their operations.[47] As this decision places responsibility for figuring out how to maintain overall water quality on the EPA, businesses, and municipalities will be able to save money and resources in determining how discharge levels impact water quality.[48] From an industry perspective, this decision will foster a more business-friendly environment where regulatory expectations are clear, achievable, and manageable.
B. Environmental Advocates’ Concerns
Conversely, environmental advocates have expressed serious concerns about the implications of the Supreme Court’s decision for the future of water quality protections.[49] While the ruling may provide regulatory clarity, it potentially undermines the flexibility and effectiveness of the CWA, particularly in situations where multiple dischargers contribute to pollution in a single body of water. End-result water quality standards, which were previously allowed by the EPA, provided a comprehensive approach to addressing cumulative pollution impacts on water bodies.[50] This approach was crucial in cases where irregular pollution could degrade water quality over time, even if each discharger complied with specific effluent limits.[51]
By eliminating the EPA’s ability to set broad end-result standards, the Court’s decision risks narrowing the scope of water quality protections by potentially allowing water bodies to deteriorate, even if individual dischargers meet their specific permit conditions.[52] This shift could have particularly harmful effects in complex, multi-discharger scenarios, where pollution from multiple sources interacts and exacerbates water quality problems.[53] Additionally, the need for the EPA to gather more detailed discharge data to develop specific effluent limits for each facility could lead to delays in the permitting process, hindering the timely protection of water bodies and slowing the pace of environmental progress.[54] Environmental advocates fear that the ruling will result in fragmented water quality protections, with less comprehensive oversight and weaker safeguards for vulnerable ecosystems and communities.
C. Flawed Interpretation of the CWA
Writing for the dissent, Justice Barrett argues that the majority’s interpretation of §1311(b)(1)(C) is contrary to the plain language of the statute.[55] The statute explicitly states that the EPA must impose “any more stringent limitation” that is “necessary to meet… or required to implement any applicable water quality standard.”[56] The majority, however, concluded that the EPA lacked the authority to impose broad, end-result water quality standards because they do not constitute a “limitation” in the ordinary sense.[57] Justice Barrett refutes this claim, asserting that a prohibition on violating water quality standards is undoubtedly a restriction on a discharger’s permit, as it places a clear limitation on the extent to which pollutants can enter a water body.[58]
To illustrate this point, Justice Barrett draws comparisons to everyday life such as: “A doctor could impose a ‘limitation’ on a patient’s diet by telling the patient that she must lose 20 pounds over the next six months, even if the doctor does not prescribe a specific diet and exercise regimen. And an airline could impose a ‘limitation’ on the weight of checked bags, even though it does not tell passengers what items to pack.”[59] Similarly, an EPA limitation requiring compliance with water quality standards does not prescribe specific methods for achieving compliance, but it unquestionably limits what dischargers can do. The majority’s interpretation, she contends, is a narrowing of the statute’s text that disregards Congress’s intent to ensure stronger water quality protections.[60]
Beyond its flawed interpretation, Justice Barrett warns that the majority’s ruling will have severe practical consequences for water quality enforcement. By prohibiting the EPA from setting general water quality conditions, the decision forces the agency to establish individualized, highly specific effluent limitations for each permittee.[61] This shift places an immense administrative burden on the EPA, as the EPA often lacks the adequate data and information to issue highly individualized effluent limitations on permits.[62] The lack of resources and data for the EPA could result in lengthy delays or denials of NPDES permits.[63] In the words of Justice Barrett, it might be “preferable for EPA to impose broadly worded conditions in its permits than to deny permits altogether and potentially shut down San Francisco’s sewer system.”[64]
Justice Barrett’s dissent provides a more compelling interpretation of the CWA, which aligns with both the statutory text and the Act’s overarching purpose. As she correctly points out, the CWA explicitly authorizes the EPA to impose “any more stringent limitation” necessary to meet water quality standards.[65] The majority’s distinction between specific effluent limits and broader water quality requirements is not grounded in the statute’s language or intent. Rather, the majority’s interpretation restricts the EPA’s ability to enforce the very protections that Congress designed the CWA to uphold. By forcing the EPA to rely solely on individualized, specific effluent limitations, the ruling places an immense burden on regulators, potentially delaying the permitting process and weakening enforcement efforts.[66] This immense burden could lead to a decline in water quality because the EPA lacks the necessary tools to enforce them effectively.[67]
IV. Conclusion
The Supreme Court’s ruling in City and County of San Francisco v. EPA marks a significant shift in the regulatory landscape of the CWA, limiting the EPA’s ability to impose broad, end-result water quality standards. While the majority framed its decision as a victory for regulatory certainty, the ruling undermines the EPA’s capacity to effectively address the cumulative and complex nature of water pollution.[68] By stripping the agency of its authority to impose end-result limitations, the Court has made it more difficult for the EPA to ensure that the nation’s waterways remain clean, healthy, and safe for public use.
The CWA was not meant to be a narrow, technical framework that regulates individual discharges in isolation. The CWA was designed to be a powerful tool to protect the integrity of the nation’s water. Justice Barrett’s dissent recognizes this reality, and her reasoning should serve as a foundation for future efforts to ensure that the EPA retains the authority to protect the nation’s waterways.
[1] “The River Caught Fire”: The Cuyahoga River Fire of 1969, Collaborative for Health & Env’t, https://www.healthandenvironment.org/resources/resource-library/eh-history/the-cuyahoga-river-fire-of-1969 (last visited Mar. 23, 2025).
[2] Micheal Rotman, Cuyahoga River Fire, Cleveland Hist., https://clevelandhistorical.org/items/show/63 (last visited Mar. 23, 2025).
[3] Summary of the Clean Water Act, EPA, https://www.epa.gov/laws-regulations/summary-clean-water-act (last visited Mar. 23, 2025).
[4] About NPDES, EPA, https://www.epa.gov/npdes/about-npdes (last visited Mar. 23, 2025).
[5] Id.
[6] Id.
[7] Id.
[8] City and Cnty. of San Francisco, California v. Env’t Prot. Agency, 145 S. CT 704, 704 (2025).
[9] Id.
[10] Id.
[11] History of the Clean Water Act, EPA, https://www.epa.gov/laws-regulations/history-clean-water-act (last visited Mar. 23, 2025).
[12] Rotman, supra note 2.
[13] History of the Clean Water Act, supra note 11.
[14] NPDES Permit Basics, EPA, https://www.epa.gov/npdes/npdes-permit-basics (last visited Mar. 23, 2025).
[15] Id.
[16] Id.
[17] Id.
[18] Id.
[19] Permit Limits – TBELs and WQBELs, EPA, https://www.epa.gov/npdes/permit-limits-tbels-and-wqbels (last visited Mar. 23, 2025).
[20] Id.
[21] Id.
[22] Id.
[23] TBELs and WQBELs: What is the Difference?, EHS Daily Advisor (Jun. 19, 2017), https://ehsdailyadvisor.blr.com/2017/06/tbels-wqbels-difference/.
[24] City and Cnty. of San Francisco, California v. Env’t Prot. Agency, 145 S. CT 704, 710 (2025).
[25] Id.
[26] Rapanos v. United States, 547 U.S. 715, 732 (2006).
[27] Sackett v. Env’t Prot. Agency, 596 U.S. 651, 684 (2023).
[28] City and Cnty. of San Francisco, California, 145 S. Ct. at 715.
[29] Id.
[30] Id.
[31] Id.
[32] Id.
[33] Id.
[34] Id.
[35] Id.
[36] Id.
[37] Id.
[38] Id. at 714.
[39] Id. at 716.
[40] Adam Reynolds, Supreme Court Limits EPA’s Ability to Condition Pollution on Water Quality, The State Energy & Env’t Impact Ctr. (Mar. 13, 2025), https://stateimpactcenter.org/insights/supreme-court-limits-epas-ability-to-condition-pollution-on-water-quality.
[41] City and Cnty. of San Francisco, California, 145 S. Ct. at 720.
[42] Jordan Rodriguez, San Francisco v. EPA: Supreme Court Strikes Down EPA’s “End-Result” Permit Requirements, Nat’l L. Rev. (Mar. 7, 2025), https://natlawreview.com/article/san-francisco-v-epa-supreme-court-strikes-down-epas-end-result-permit-requirements.
[43] Id.
[44] Id.
[45] Tommy Beaudreau et al, San Francisco v. EPA: Impact on Clean Water Act Permittees, WilmerHale (Mar. 6, 2025), https://www.wilmerhale.com/en/insights/client-alerts/20250306-san-francisco-vs-epa-impact-on-clean-water-act-permittees.
[46] Id.
[47] Id.
[48] Id.
[49] Rodriguez, supra note 42.
[50] City and Cnty. of San Francisco, California v. Env’t Prot. Agency, 145 S. CT 704, 712 (2025).
[51] Rodriguez, supra note 42.
[52] Id.
[53] Id.
[54] Beaudreau, supra note 45.
[55] City and Cnty. of San Francisco, California, 145 S. Ct. at 720 (Barrett, J., dissenting).
[56] Id.
[57] Id. at 722.
[58] Id. at 723.
[59] Id.
[60] Id. at 724.
[61] Id.
[62] Id.
[63] Id.
[64] Id.
[65] Id. at 721.
[66] Beaudreau, supra note 45.
[67] Id.
[68] Rodriguez, supra note 42.
Cover Photo by Gowtham AGM on Unsplash.
