By Nicole Granquist, Meghan Quinn and Meredith Nikkel
On January 14, 2021, the U.S. Environmental Protection Agency (EPA) finalized guidance regarding the implementation of the U.S. Supreme Court’s decision in County of Maui, Hawaii v. Hawaii Wildlife Fund, 590 U.S. ___ (2020) (Maui), which established a “functional equivalent” test to determine when discharges to groundwater that ultimately reach surface waters should be regulated under the federal Clean Water Act in the same manner as a direct discharge to surface waters (Maui Guidance). The Maui Guidance states that any discharge must meet certain “baseline permitting principles” comprised of threshold conditions that trigger the National Pollutant Discharge Elimination System (NPDES) Permit requirement, and the type of analysis permit writers currently conduct for surface water discharges. In doing so, the Maui Guidance sets forth an additional factor that should be evaluated when determining whether a discharge to groundwater requires an NPDES Permit—“the design and function of the treatment system”—and provides guidance regarding the types of discharges and associated treatment systems for which NPDES Permits will not be required.
Background—The Maui Decision
In Maui, the Supreme Court held that an NPDES permit is required “if the addition of the pollutants through groundwater is the functional equivalent of a direct discharge from the point source into navigable waters.” According to the Court, evaluation of whether a discharge of a pollutant to groundwater is the “functional equivalent of a direct discharge from the point source into navigable waters,” requires the application of the following seven factors: 1) the pollutant’s travel time between the discharge point and the navigable water; 2) the distance traveled; 3) the material through which the discharge travels; 4) dilution or chemical changes during travel; 5) the amount of pollutant entering the navigable water as compared to the amount that leaves the point source; 6) the way or location the pollutant enters the navigable water; and 7) the degree to which the pollution has retained its identity upon reaching the navigable water. The opinion makes clear that the list is not exhaustive, but notes that time and distance may be the most important factors. (See: https://www.supremecourt.gov/opinions/19pdf/18-260_jifl.pdf)
The Maui Guidance Summary
The primary focus of the Maui Guidance appears to be a reduction in the number of inquiries from the regulated community regarding whether or not an NPDES Permit is required for a particular discharge. To eliminate a number of those inquiries, the Maui Guidance describes “baseline permitting principles” that seek to resolve questions from the regulated community (and potentially frivolous litigation). The baseline permitting principles, which consume the majority of the eight-page guidance memorandum, are primarily a recitation of the elements that traditionally trigger the NPDES Permit requirement as applied to surface waters.
By confirming that all discharges are subject to the described framework, the EPA adopts an additional factor that:
. . .may prove relevant and thus should be considered when performing a ‘functional equivalent’ analysis: the design and performance of the system or facility from which the pollutant is released.
The Maui Guidance indicates that an evaluation of the design and performance of the facility or system from which a pollutant is released is customary when the agency evaluates whether a direct discharge requires an NPDES Permit. The Maui Guidance goes one step further by describing treatment system designs and discharge point locations that are unlikely to be subject to the NPDES Permit requirement, as well as the influence of such system component designs and locations on the composition of any pollutants discharged to groundwater that ultimately reach surface water. For example:
. . .the point of discharge may be engineered to direct the pollutant into a subsurface aquitard or to a surface area designed to slow the transit time of a pollutant that ultimately reaches a water of the United States.
EPA also clarifies that the agency anticipates that the issuance of NPDES Permits for discharges of pollutants to groundwater:
. . . will continue to be a small percentage of the overall number of NPDES permits issued following application of the Supreme Court’s ‘functional equivalent’ analysis.
To emphasize this point, the Maui Guidance reminds practitioners that: 1) the discharge must first meet the threshold requirements that trigger the NPDES Permit requirement; and 2) all of the factors comprising the “functional equivalent” test must be applied to the discharge. In other words, a demonstration that pollutants associated with a point source discharge merely reach surface waters falls short of the analysis required by the Maui decision, and would not trigger the NPDES Permit requirement for discharges to groundwater.
Conclusion and Implications
The Maui Guidance provides insight into how the EPA will apply its current NPDES Permit program framework to groundwater discharges, confirmed by the establishment of the new “design and performance” factor. Moreover, the Maui Guidance crafts a distinction between the Ninth Circuit’s “fairly traceable” standard and the Supreme Court’s “functional equivalent” test by indicating that the fact that a pollutant associated with a point source discharge to groundwater reaches surface waters is not enough to trigger NPDES Permitting.
However, whether the Maui Guidance will remain in effect is unclear, given the Biden Administration’s recent adoption of the Executive Order on Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis, which will require EPA to revisit all “regulations, orders, guidance documents, policies, and any other similar agency actions (agency actions) promulgated, issued, or adopted between January 20, 2017, and January 20, 2021” that may be inconsistent with the Biden administration’s policy on environmental protection and public health. The outcome of that review process remains to be seen. For more information about the Guidance, see:https://www.epa.gov/npdes/releases-point-source-groundwater)
![Federal District Court Denies Preliminary Injunction Over Shasta Dam Operations, Upholding U.S. Bureau of Reclamation’s Water PlanThe U.S. District Court for the Eastern District of California denied three environmental organizations’ request for a preliminary injunction requiring the U.S. Bureau of Reclamation (Reclamation) to modify its 2026 operations of Shasta Dam and Reservoir. The court classified the requested relief as a mandatory injunction and concluded that the plaintiffs failed to satisfy the heightened standard applicable to such relief. [San Francisco Baykeeper v. U.S. Bureau of Reclamation, ___F.Supp.4th___, Case No. 2:26-cv-00671-JLT-EPG (E.D. Cal. Aug. 3, 2026).] Background On March 2, 2026, San Francisco Baykeeper, the Center for Biological Diversity, and Friends of the River filed suit against Reclamation, the National Marine Fisheries Service, and several federal officials. The broader lawsuit alleges that the federal defendants violated the federal Endangered Species Act and Administrative Procedure Act in connection with Reclamation’s operation of the Central Valley Project. Among other allegations, the plaintiffs contend that Reclamation failed to comply with protective measures and incidental-take limits established by the National Marine Fisheries Service’s (NMFS’s) 2024 Biological Opinion (BiOp) for winter-run chinook salmon, Central Valley steelhead, and North American green sturgeon. The preliminary-injunction motion addressed a narrower issue: Reclamation’s operation of Shasta Dam and Reservoir during the summer and early fall of 2026. Keswick Dam prevents winter-run chinook salmon from reaching their historic upstream spawning habitat. Consequently, the survival of eggs deposited downstream depends substantially on Reclamation’s release of sufficiently cold water from Shasta Reservoir. The 2024 BiOp established a “Shasta Framework” for managing water temperature and reservoir storage while accounting for fish protection, water-delivery obligations, flood control, and other authorized project purposes. In the framework, Reclamation designated 2026 as a “Bin 2A” year based on projected end-of-April and end-of-September reservoir storage. The plaintiffs argued that the high end-of-April storage level required Reclamation to treat 2026 as a more protective Bin 1 year and preserve at least 2.4 million acre-feet of water through September unless achieving that target was impossible. Reclamation responded that the framework uses both April storage and projected September storage to make the initial classification and that the forecasts therefore supported its Bin 2A designation. The plaintiffs sued Reclamation under sections 7 and 9 of the Endangered Species Act and the Administrative Procedure Act, alleging that Reclamation was operating outside the 2024 biological opinion’s Shasta Framework. The plaintiffs then sought emergency relief requiring Reclamation to reduce releases from Shasta Reservoir, prepare a new operating plan, and operate consistently with the plaintiffs’ interpretation of the Bin 1 requirements. The court denied the plaintiffs’ request for a temporary restraining order on July 9, 2026, and subsequently denied their motion for a preliminary injunction. The District Court’s Ruling Although the order is not a final ruling on the merits, it indicates that the court views Reclamation’s interpretation of the Shasta Framework as better supported by the governing documents. The court expressly stated that the plaintiffs did not appear likely to succeed on the claim advanced in the motion and failed to make the stronger showing required for a mandatory injunction. In its ruling, the District Court first rejected the plaintiffs’ argument that the requested injunction would merely preserve the status quo. The proposed relief would have required Reclamation to conduct new modeling, prepare and implement a new temperature-management plan, and materially change its reservoir operations. Because the requested order would compel affirmative action, the court treated it as a mandatory injunction. The plaintiffs therefore had to demonstrate that the law and facts clearly favored their position, not merely that they were likely to prevail. Second, the court found Reclamation’s interpretation of the 2024 BiOp more persuasive. Although language in Table 25 of the BiOp supported the plaintiffs’ position, the court concluded that the underlying Proposed Action, decision tree, and operational modeling supported using both projected April and September storage to determine the applicable Bin. The court suggested that Table 25 may have inaccurately summarized the end-of-April storage ranges described in the Proposed Action. The court used the interpretive framework from Kisor v. Wilkie as guidance but did not ultimately rely on agency deference. The Court directly addressed the interpretations of the BiOp, and underlying data to support and, in doing so, made clear that the decision was not based on any level of agency-deference but, instead, based on a finding that Reclamation’s position was more factually supported and, therefore, did not assess questions of deference. Conclusion and Implications The ruling leaves Reclamation’s 2026 Shasta operations unchanged by the requested federal injunction. It does not, however, finally approve those operations or resolve the plaintiffs’ broader allegations concerning incidental take, reinitiation of ESA consultation, or the validity and application of the 2024 BiOp. Legally, the decision underscores the high threshold plaintiffs face when seeking mandatory injunction against federal agency operations, particularly when relying on narrow claims regarding BiOp framework, and addresses the importance of a fact-based assessment, while declining to address to questions of agency deference. The court’s order is available here: https://www.courthousenews.com/wp-content/uploads/2026/08/baykeeper-injuction-denied-ruling.pdf (Stephanie Cook, Miles Krieger)](https://argentco.com/wp-content/uploads/2019/09/ARTICLES-Land_Fog-230x100.jpg "Federal District Court Denies Preliminary Injunction Over Shasta Dam Operations, Upholding U.S. Bureau of Reclamation’s Water PlanThe U.S. District Court for the Eastern District of California denied three environmental organizations’ request for a preliminary injunction requiring the U.S. Bureau of Reclamation (Reclamation) to modify its 2026 operations of Shasta Dam and Reservoir. The court classified the requested relief as a mandatory injunction and concluded that the plaintiffs failed to satisfy the heightened standard applicable to such relief. [San Francisco Baykeeper v. U.S. Bureau of Reclamation, ___F.Supp.4th___, Case No. 2:26-cv-00671-JLT-EPG (E.D. Cal. Aug. 3, 2026).] Background On March 2, 2026, San Francisco Baykeeper, the Center for Biological Diversity, and Friends of the River filed suit against Reclamation, the National Marine Fisheries Service, and several federal officials. The broader lawsuit alleges that the federal defendants violated the federal Endangered Species Act and Administrative Procedure Act in connection with Reclamation’s operation of the Central Valley Project. Among other allegations, the plaintiffs contend that Reclamation failed to comply with protective measures and incidental-take limits established by the National Marine Fisheries Service’s (NMFS’s) 2024 Biological Opinion (BiOp) for winter-run chinook salmon, Central Valley steelhead, and North American green sturgeon. The preliminary-injunction motion addressed a narrower issue: Reclamation’s operation of Shasta Dam and Reservoir during the summer and early fall of 2026. Keswick Dam prevents winter-run chinook salmon from reaching their historic upstream spawning habitat. Consequently, the survival of eggs deposited downstream depends substantially on Reclamation’s release of sufficiently cold water from Shasta Reservoir. The 2024 BiOp established a “Shasta Framework” for managing water temperature and reservoir storage while accounting for fish protection, water-delivery obligations, flood control, and other authorized project purposes. In the framework, Reclamation designated 2026 as a “Bin 2A” year based on projected end-of-April and end-of-September reservoir storage. The plaintiffs argued that the high end-of-April storage level required Reclamation to treat 2026 as a more protective Bin 1 year and preserve at least 2.4 million acre-feet of water through September unless achieving that target was impossible. Reclamation responded that the framework uses both April storage and projected September storage to make the initial classification and that the forecasts therefore supported its Bin 2A designation. The plaintiffs sued Reclamation under sections 7 and 9 of the Endangered Species Act and the Administrative Procedure Act, alleging that Reclamation was operating outside the 2024 biological opinion’s Shasta Framework. The plaintiffs then sought emergency relief requiring Reclamation to reduce releases from Shasta Reservoir, prepare a new operating plan, and operate consistently with the plaintiffs’ interpretation of the Bin 1 requirements. The court denied the plaintiffs’ request for a temporary restraining order on July 9, 2026, and subsequently denied their motion for a preliminary injunction. The District Court’s Ruling Although the order is not a final ruling on the merits, it indicates that the court views Reclamation’s interpretation of the Shasta Framework as better supported by the governing documents. The court expressly stated that the plaintiffs did not appear likely to succeed on the claim advanced in the motion and failed to make the stronger showing required for a mandatory injunction. In its ruling, the District Court first rejected the plaintiffs’ argument that the requested injunction would merely preserve the status quo. The proposed relief would have required Reclamation to conduct new modeling, prepare and implement a new temperature-management plan, and materially change its reservoir operations. Because the requested order would compel affirmative action, the court treated it as a mandatory injunction. The plaintiffs therefore had to demonstrate that the law and facts clearly favored their position, not merely that they were likely to prevail. Second, the court found Reclamation’s interpretation of the 2024 BiOp more persuasive. Although language in Table 25 of the BiOp supported the plaintiffs’ position, the court concluded that the underlying Proposed Action, decision tree, and operational modeling supported using both projected April and September storage to determine the applicable Bin. The court suggested that Table 25 may have inaccurately summarized the end-of-April storage ranges described in the Proposed Action. The court used the interpretive framework from Kisor v. Wilkie as guidance but did not ultimately rely on agency deference. The Court directly addressed the interpretations of the BiOp, and underlying data to support and, in doing so, made clear that the decision was not based on any level of agency-deference but, instead, based on a finding that Reclamation’s position was more factually supported and, therefore, did not assess questions of deference. Conclusion and Implications The ruling leaves Reclamation’s 2026 Shasta operations unchanged by the requested federal injunction. It does not, however, finally approve those operations or resolve the plaintiffs’ broader allegations concerning incidental take, reinitiation of ESA consultation, or the validity and application of the 2024 BiOp. Legally, the decision underscores the high threshold plaintiffs face when seeking mandatory injunction against federal agency operations, particularly when relying on narrow claims regarding BiOp framework, and addresses the importance of a fact-based assessment, while declining to address to questions of agency deference. The court’s order is available here: https://www.courthousenews.com/wp-content/uploads/2026/08/baykeeper-injuction-denied-ruling.pdf (Stephanie Cook, Miles Krieger)")
