If you have ever received a 60-Day Notice under the Clean Water Act (CWA), you know the drill. A private plaintiff sends the letter. The government rarely steps in. The plaintiff files suit, seeks civil penalties and attorneys’ fees and litigates or settles the case without any meaningful federal involvement. That process has operated largely unchallenged for over fifty years.
But that may change. In three recent CWA cases, defendants have argued that private plaintiffs lack constitutional authority to exercise what amounts to executive enforcement power. In a separate Clean Air Act case, the Department of Justice (DOJ) moved to intervene and dismiss a citizen suit, asserting the government’s right to stop a private enforcement action it opposes. No court has ruled on either theory, but the arguments draw on the same Article II principles the Supreme Court has applied in recent separation-of-powers decisions, and the outcome could reshape not just environmental citizen suits but any federal scheme that relies on private enforcement of public law.
How Environmental Citizen-Suit Provisions Work
Most major federal environmental statutes include a citizen-suit provision. The CWA’s version, Section 505, is typical. A private plaintiff who believes a facility is violating its permit may file a lawsuit in federal court, but only after following a prescribed process.
First, the plaintiff must send a 60-Day Notice to the alleged violator, the EPA Administrator, and the relevant state agency. That notice gives the government an opportunity to act. If EPA or the state commences and is diligently prosecuting its own enforcement action within the 60-day period, the citizen suit is barred. If the government does not act, the plaintiff may file suit.
A court in a citizen suit may order injunctive relief requiring the defendant to comply with its permit, impose civil penalties payable to the U.S. Treasury, and award attorneys’ fees and litigation costs to the prevailing party. The government retains the right to intervene at any time after the suit is filed.
Congress included analogous provisions in the Clean Air Act (CAA), the Resource Conservation and Recovery Act (RCRA), the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the Endangered Species Act (ESA), and other environmental statutes. The statutes differ in the details, but their shared reliance on private enforcement means the constitutional arguments now being raised in the CWA cases could extend to citizen suits under any of them.
The Executive Power Cases
Three recent CWA citizen suits share a common thread. In each, the defendant partnered with Pacific Legal Foundation, a law firm that specializes in constitutional and limited-government cases. In all three cases, the defendants raised the same core constitutional challenge: Congress cannot authorize private plaintiffs to exercise Article II executive enforcement power.
The defendants’ motions invoke several theories. Specifically, they argue that seeking civil penalties payable to the U.S. Treasury is “a quintessentially executive power” that Congress cannot hand to private plaintiffs without agency supervision. Defendants contend that private plaintiffs who file suit after the Executive declines to act interfere with the President’s prosecutorial discretion, violating the Executive Vesting and Take Care Clauses. They also distinguish personal compensation from Treasury penalties and public injunctive relief, which they characterize as public remedies that only the government should pursue. As an alternative, the defendants argue that repeat citizen-suit plaintiffs exercise significant federal authority from a continuing position without the appointment required for a federal officer, violating the Appointments Clause.
These motions also draw on the broader Unitary Executive Theory. That theory holds that Article II vests all federal executive power in the President alone and that any exercise of enforcement authority must remain subject to presidential control. The Supreme Court has applied that principle in recent decisions expanding presidential control over executive-branch actors, including Seila Law LLC v. CFPB, 591 U.S. 197 (2020), and Trump v. Slaughter, 146 S. Ct. 2283 (2026). The motions cite both decisions. With the theory now apparently commanding support from all six conservative justices, the defendants appear to be leveraging the current Court’s embrace of the Unitary Executive Theory to extend it to citizen-suit provisions across federal environmental law.
In Tennessee Riverkeeper, Inc. v. City of Springfield, No. 3:26-cv-00284 (M.D. Tenn.), Tennessee Riverkeeper sued the city over alleged NPDES permit violations at a municipal wastewater treatment plant. Riverkeeper had sent a notice of intent to sue in November 2025, then filed suit in March 2026, alleging overflows, operation-and-maintenance releases, and reporting violations. The complaint sought injunctive relief, civil penalties, and litigation costs. Springfield moved to dismiss on July 20, 2026, noting that Springfield was the thirty-first CWA citizen suit Riverkeeper had filed since 2010. Tennessee Riverkeeper voluntarily dismissed the case on August 21, 2026, before the court ruled.
A similar case, Tennessee Riverkeeper, Inc. v. City of Luttrell, Tennessee, No. 3:25-cv-00541 (E.D. Tenn.), involved alleged permit violations at another municipal wastewater facility. The city moved to dismiss on the same constitutional grounds on December 5, 2025. Riverkeeper voluntarily dismissed that case shortly after the defendant filed its motion.
Riverkeeper did not explain whether these constitutional arguments influenced either dismissal. Two voluntary dismissals following substantially similar motions, however, suggest the challenges carry practical weight. They may affect whether environmental groups pursue cases against defendants prepared to seek a ruling on the constitutional questions.
In West Virginia Rivers Coalition v. Amsted Graphite Materials LLC, No. 1:26-cv-00046-TSK (N.D.W. Va.), environmental groups allege CWA violations at a carbon and graphite manufacturing facility. EPA and the West Virginia Department of Environmental Protection had already entered into compliance agreements with the facility, imposed penalties, and established a schedule for facility upgrades. The defendant moved to dismiss on August 5, 2026, raising the same constitutional arguments discussed above. Unlike the Tennessee cases, Amsted remains pending and could produce the first merits ruling on these arguments.
The X.AI Case
In NAACP v. X.AI Corp., No. 3:26-cv-00074-DMB-JMV (N.D. Miss.), the NAACP alleged that gas-fired turbines supplying xAI data centers operated without required Clean Air Act permits. The NAACP characterizes the collection of more than 50 turbines as a single “major source” of air pollution and seeks civil penalties of $124,426 per day of violation, plus injunctive relief ordering xAI to stop operating the turbines until it obtains the required permits.
DOJ took the unusual step of moving to intervene and dismiss the case on June 15, 2026, arguing that the “United States’ right to intervene includes a right to dismiss this entire enforcement action” and that the CAA “does not authorize citizen-enforcement actions that seek relief the governmental enforcers choose to forgo.” DOJ also invoked case-specific interests, arguing that xAI’s data centers are “a matter of paramount national security” because the Grok AI platform supports Department of War military operations. The State of Mississippi agreed with DOJ’s determination that the NAACP’s enforcement action was unwarranted.
DOJ’s approach differs from the constitutional challenges discussed above. Rather than asking the court to invalidate the citizen-suit provision, DOJ argued for a statutory interpretation: the federal government’s unconditional right to intervene “at any time” necessarily includes the right to dismiss. DOJ warned that if the court disagreed, allowing a private enforcement action to proceed over the government’s objection would raise “serious constitutional questions” under Article II’s Vesting and Take Care Clauses. DOJ framed this as constitutional avoidance: the statute should be read to permit dismissal rather than force an interpretation that creates Article II problems.
DOJ also argued that the only alternative under the current statutory framework would be for the government to “diligently prosecute” its own enforcement action to displace the citizen suit. But DOJ said that would “only exacerbate the Article II violation by stripping the Executive Branch of discretion to determine that no enforcement action is the proper course.”
Why This Goes Beyond Citizen Suits
The arguments in these cases are framed around environmental citizen suits, but they rest on Article II principles that apply across federal law. If a court holds that private plaintiffs cannot exercise executive enforcement power without presidential control, that reasoning could reach any federal statute that authorizes private parties to seek public remedies on the government’s behalf. The defendants’ motions in the above-described cases cite the same Seila Law and Trump v. Slaughter precedent that the Court has applied to limit the independence of federal agencies, remove executive officers, and consolidate enforcement authority in the President. The question is whether the Court will extend that logic from how the government is structured to who can enforce federal law at all.
California Implications
California has more CWA citizen-suit activity than any other state, particularly involving alleged IGP violations. See https://www.allenmatkins.com/real-ideas/a-cottage-industry-the-economics-of-cwa-citizen-suit-enforcement.html. If courts accept these challenges, pending suits and the framework for future suits could be called into question. The fee-driven enforcement model that has developed around CWA citizen suits depends on the validity of the citizen-suit provision.
California Stormwater Defense is published by Allen Matkins Leck Gamble Mallory & Natsis LLP. Nothing in this post constitutes legal advice. Contact us for a consultation specific to your facility.