By: Daniel Tillman

The primary purpose of the Clean Water Act (CWA) is to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”[1]  In order to achieve this objective, the Act prohibits the “discharge of any pollutant by any person” and defines “discharge of any pollutant” as “any addition of any pollutant to navigable waters from any point source.”[2]  Determining the jurisdictional reach of the CWA and whether one needs to acquire a permit to discharge pollutants into a body of water has recently led to a flurry of litigation in the courts.[3] Specifically, following the plurality decision in Rapanos v. United States[4], lower courts and the federal agencies that administer the CWA have struggled to define “waters of the United States.”[5]  This led the circuits to split on the issue of whether the CWA’s jurisdiction covers discharges into groundwater that eventually flows into a navigable-in-fact water.[6]

The Supreme Court has recently asked the Solicitor General to weigh in on this issue and file briefs in Hawaii Wildlife Fund v. County of Maui andUpstate Forever v. Kinder Morganto express the views of the United States on or before January 4, 2019.[7]  Proponents for extending the CWA’s jurisdiction argue that regulating the discharge of groundwater aligns with the overall purpose of the CWA to protect navigable waters.[8] However, understanding the nature of groundwater and its connection to surface water is important in assessing whether the CWA’s jurisdiction applies to discharges into groundwater.[9]  Groundwater has the special property of retaining the pollutants that enter it for long periods of time, making it difficult to find the origins of the pollutant for liability purposes.[10]  Should the Supreme Court find that the CWA’s jurisdiction extends to groundwater discharge, companies may find a significant increase in expenses to maintain a monitoring system that checks the pollutant levels that enter groundwater.[11]  One can expect further litigation on this issue as the circuits wait for the Supreme Court to weigh in on whether discharges into groundwater fall within the CWA’s jurisdiction.[12]

[1]SeeHawaii Wildlife Fund v. County of Maui, 886 F.3d 737, 744 (9th Cir. 2018) (citing 33 U.S.C. § 1251(a)).

[2]See 33 U.S.C. § 1362(14) (defining a “point source” as “any discernible, confined and discrete conveyance from which pollutants are or may be discharged”).

[3]See Sackett v. EPA, 566 U.S. 120, 132 (2012) (Alito, J., concurring) (“The reach of the Clean Water Act is notoriously unclear. Any piece of land that is wet at least part of the year is in danger of being classified . . . as wetlands covered by the Act . . . .”).

[4]547 U.S. 715, 782 (2006) (plurality opinion) (developing two separate tests to determine what water bodies fall within the CWA’s definition for “waters of the United States”). 

[5]SeeDefinition of “Waters of the United States” – Recodification of Preexisting Rule, 83 Fed. Reg. 32227, 32228 (July 12, 2018) (to be codified at 33 C.F.R. pt. 328) [hereinafter SNPRM] (discussing the recent rulemakings that have been passed to clarify the reach of the Clean Water Act); see alsoLowell M. Rothschild, The Practical Application of the Significant Nexus Test: The Final Waters of the US Rule, Nat’l L. Rev. (June 8, 2015), (discussing the challenges left to the agencies that administer the CWA by not having a clear test that defines “waters of the United States”).

[6]See Hawaii Wildlife Fund, 886 F.3d at 749 (concluding that discharges into groundwater that are fairly traceable from the point source to a navigable water falls within the CWA’s jurisdiction). But seeUpstate Forever v. Kinder Morgan Energy Partners, 887 F.3d 637, 651 (4th Cir. 2018) (finding that discharges into groundwater from a coal-fired power plant that flows into a navigable water does not fall within the CWA’s jurisdiction).

[7]See W. Parker Moore et al.,Justices Request the Government’s View on CWA Discharge Cases, Nat’l L. Rev.(Dec. 5, 2018),

[8]See Allison Kvien, Is Groundwater that is Hydrologically Connected to Navigable Waters Covered Under the CWA?: Three Theories of Coverage & Alternative Remedies for Groundwater Pollution, 16 Minn. J. L. Sci. & Tech.957, 961 (2015) (noting that it is important to have a basic understanding of the hydrology of groundwater and surface water to consider whether groundwater counts as a point source).


[10]See Iyyanki Muralikrishna & Valli Manickam, Environmental Management: Science and Engineering for Industry, 209 (2017) (noting that an important aspect of groundwater pollution is that it may persist underground for years, decades, or even centuries).  

[11]See Janny Choy, High Quality Groundwater Data Isn’t Always Easy or Cheap, But it is Necessary, Stanford: Water in the West(Sept. 14, 2016),’t-always-easy-or-cheap-it-necessary (explaining that developing a robust system of monitoring wells are expensive and factors such as geology, casing, well depth, and borehole diameter affect the costs).

[12]See Richard S. Davis et al.,Pair of Clean Water Act Decisions Creates Circuit Split Over Discharges to Groundwater, Nat’l L. Rev.(Sept. 25, 2018),

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