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Does the Clean Water Act Regulate Discharges of Pollutants to Hydrologically Connected Groundwater? Federal Courts Disagree

January 27, 2016

The Clean Water Act (“CWA”) prohibits the discharge of pollutants into “waters of the United States”[1] without a valid National Pollutant Discharge Elimination System (“NPDES”) permit.[2] The statute offers notoriously scant guidance as to what “waters of the United States” actually means. As a result, whether the CWA applies to a given water body is often the subject of controversy and confusion. The EPA and the U.S. Army Corps of Engineers’ Clean Water Rule—currently beset by political, legal and legislative challenges[3]—attempts to clarify this important term. But the Clean Water Rule is silent on an important question that continues to divide federal courts: does the CWA apply to releases of pollutants into groundwater that eventually migrate into waters of the United States?

In the last several months, at least three federal district courts have considered this question. Two courts, both within the Fourth Circuit, have held that the CWA governs discharges into groundwater that is hydrologically connected to jurisdictional waters of the United States. The third, from the Eastern District of Pennsylvania, would permit CWA jurisdiction over groundwater discharges in far more limited circumstances. Still other courts view the CWA as inapplicable to groundwater, no matter its ultimate connection to surface water bodies. This article reviews these recent decisions, explores the split among federal courts, and considers the implications of this unsettled area of the law.


The CWA prohibits “the discharge of any pollutant by any person” “except as in compliance” with the act.[4] The act defines “discharge of a pollutant” as “any addition of any pollutant to navigable waters from any point source,” and “navigable waters” as “waters of the United States.”[5] A “point source,” in turn, is “any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged.”[6] In order to discharge pollutants in compliance with the act, parties typically obtain NPDES permits from the EPA or an authorized state agency.[7] The CWA also authorizes private citizens to bring suit for CWA violations after 60 days’ notice.[8]

It has long been more or less accepted that isolated groundwater itself does not fall with the umbrella of “waters of the United States.” Thus, EPA and the Army Corps of Engineers “have never interpreted ‘waters of the United States’ to include groundwater.”[9] This is not to say, however, that discharges into groundwater always fall beyond the CWA’s reach. Specifically, federal courts have still not reached consensus as to whether the CWA applies to pollutants that are discharged into groundwater and subsequently migrate into surface water bodies.

Recent District Court Decisions

Yadkin Riverkeeper, Inc. v. Duke Energy Carolinas, LLC[10] centered around Duke Energy’s disposal of coal ash in unlined lagoons near the Yadkin River.[11] Riverkeeper filed a CWA citizen suit, alleging, among other things, that pollutants leached from the lagoons into groundwater, and from there into surface waters covered by the CWA.[12] Notably, Riverkeeper did not claim that the groundwater underlying the lagoons was itself a point source or waters of the United States.[13] Instead, it based its claim solely on the theory that “the coal ash lagoons are point sources and the groundwater beneath the lagoons serves as a conduit between the point source lagoons and the Yadkin River.”[14] Duke filed a motion to dismiss these claims, arguing in part that “the CWA does not regulate the discharge of pollutants into the groundwater.”[15]

After acknowledging that courts are divided on the issue, the United States District Court for the Middle District of North Carolina agreed with those courts that have found the CWA applicable where “pollutants travel from a point source to navigable waters through hydrologically connected groundwater.”[16] Among these cases is Hawai‘i Wildlife Fund v. Cty. of Maui,[17] a recent decision from the District of Hawai‘i. The court also deemed persuasive the reasoning of the Northern District of California in another recent case:

“[I]t would hardly make sense for the CWA to encompass a polluter who discharges pollutants via a pipe running from the factory directly to the riverbank, but not a polluter who dumps the same pollutants into a man-made settling basin some distance short of the river and then allows the pollutants to seep into the river via the groundwater.”[18]

The court also noted that EPA on certain occasions announced that discharges into hydrologically connected groundwater are governed by the CWA.[19]

Sierra Club v. Virginia Elec. & Power Co.,[20] out of the Eastern District of Virginia, presents similar facts and reaches a similar result. There, Sierra Club brought suit against Dominion Virginia Power alleging CWA violations stemming from Dominion’s disposal of coal ash.[21] Specifically, Sierra Club claimed that Dominion’s coal-ash disposal practices introduced pollutants into groundwater that then contaminated jurisdictional surface waters.[22] As in Yadkin Riverkeeper, Sierra Club did not claim the affected groundwater was itself a water of the United States; instead, the organization focused on the hydrological connection to surface water. Dominion filed a motion to dismiss, arguing that the Clean Water Act does not regulate such discharges.[23] Finding Yadkin Riverkeeper persuasive, the trial court agreed with Sierra Club and denied Dominion’s motion to dismiss.[24]

The Eastern District of Pennsylvania took a different approach in Tri-Realty Co. v. Ursinus Coll.[25] Plaintiff Tri-Realty alleged that releases from Ursinus College underground storage tanks (“USTs”) resulted in CWA violations.[26] In Tri-Realty, contaminants from the leaking USTs appear to have migrated beneath the surface into groundwater, traveled along the channel of an underground stormwater pipe, and eventually emerged at the foot of a hillside. From there, the contaminants seeped into Bull Hollow Run, a natural drainage feature connected (according to Ursinus, only via groundwater) to a navigable creek.[27] Ursinus constructed an impoundment in order to contain these pollutants, with a spillway that diverted overflow water into a drainage swale and ultimately Bull Hollow Run.[28]

Unlike Yadkin Riverkeeper and Sierra Club, the Tri-Realty court focused not on the hydrological connection between the groundwater beneath the Ursinus USTs and the creek, but whether contaminants flowed through a point source on the way there. In dismissing Ursinus’s summary judgment motion in pertinent part, the court made three findings relevant here. First, in direct tension with Yadkin Riverkeeper and Sierra Club, the court found that “a discharge of pollutants into navigable waters occurring only through migration of groundwater and uncontrolled soil runoff represents ‘nonpoint source’ pollution and is outside the scope of the CWA.”[29] Second, the court held that “[a] discharge of pollutants that begins through groundwater migration and is later ‘collected or channeled by man’ may constitute point source pollution.”[30] Applying this rule, the court held that Tri-Realty had introduced sufficient evidence that pollutants were discharged via a point source when contaminated groundwater (a) migrated along the stormwater pipe, (b) was contained in the impoundment, (c) exited the impoundment through the spillway and (d) traveled through the drainage swale.[31] Thus, where Yadkin Riverkeeper and Sierra Club require only a discharge from a point source into groundwater hydrologically connected to waters of the United States, Tri-Realty requires contaminated groundwater to flow through a point source before entering waters of the United States. Finally, the court found that factual disputes precluded summary judgment on the issue of whether Bull Run Hollow was sufficiently connected to the navigable creek to qualify as a tributary to navigable waters for purposes of CWA jurisdiction. The court did acknowledge, however, that “Courts are split on the issue of whether tributary groundwater may constitute “navigable waters” under the CWA.”[32]

Federal Courts Split

Yadkin Riverkeeper and Sierra Club are not the only cases to hold that the CWA regulates point-source discharges into groundwater so long as it is hydrologically connected to surface waters of the United States. A number of federal district courts have reached the same conclusion.[33] These courts have largely emphasized the same point: if a party discharges pollutants via a point source and they end up in waters of the United States, the fact that the pollutants traveled through groundwater to get there does not render the CWA inapplicable.[34]

 Tri-Realty is not the only decision to suggest that groundwater discharges might not trigger the CWA. Indeed other courts, including the First, Fifth and Seventh Circuit Courts of Appeals, have stated that discharges to groundwater do not implicate the CWA, hydrological connection or not. These decisions tend to emphasize the CWA’s legislative history. Judge Easterbrook, writing for the Seventh Circuit in Village of Oconomowoc Lake v. Dayton Hudson Corp., explained: “The omission of ground waters from the regulations is not an oversight. Members of Congress have proposed adding ground waters to the scope of the Clean Water Act, but these proposals have been defeated.”[35] Similarly, the Fifth Circuit held in Rice v. Harken Expl. Co that “the legislative history of the CWA belied any intent to impose direct federal control over any phase of pollution of subsurface waters.”[36] The First Circuit, too, stated in United States v. Johnson that the CWA does not regulate groundwater.[37]

Some have argued that cases such as Village of Oconomowoc Lake, Rice and Johnson do not fully rule out that the CWA might apply to discharges into hydrologically connected groundwater. Under this view, the apparent split among the federal courts “may largely flow from a lack of clarity by courts as to whether they are determining that groundwater itself may or may not be regulated under the Clean Water Act or are determining that groundwater may or may not be regulated when it serves as a conduit to water that is indeed regulated.”[38]

Regardless of what the courts in cases such as Village of Oconomowoc Lake and similar cases understood their task to be, a number of federal district courts have relied on them in unambiguously holding the CWA inapplicable to discharges into groundwater, even where surface water is contaminated as a result. Cape Fear River Watch, Inc. v. Duke Energy Progress, Inc., a 2014 decision from the Eastern District of North Carolina, involved a CWA citizen suit alleging facts extremely similar to Yadkin Riverkeeper and Sierra Club: pollutants associated with coal ash were contaminating a lake, including via a groundwater connection.[39] While the court denied the defendant’s motion to dismiss the case as it pertained to surface-water pollution pathways, it expressly rejected the argument that the CWA applies to discharges into groundwater.[40] Instead, the court held, “Congress did not intend for the CWA to extend federal regulatory authority over groundwater, regardless of whether that groundwater is eventually or somehow ‘hydrologically connected’ to navigable surface waters.”[41] Other district courts have reached similar conclusions.[42]

Clean Water Rule

In the Clean Water Rule, EPA and the Army Corps of Engineers codified their longstanding practice of not considering groundwater to be “waters of the United States.”[43] Hence, the Rule expressly excludes “groundwater, including groundwater drained through subsurface drainage systems” from the definition of “waters of the United States.”[44]

Unfortunately, the Rule does not specifically address the hydrologic connection question. Neither are the agencies’ statements as to groundwater jurisdiction entirely clear. For example, while they exclude “groundwater” from the definition of “waters of the United States,” EPA and the Army Corps nevertheless explain that this exclusion “does not apply to surface expressions of groundwater.”[45] Nor does the rule prevent EPA or the Corps from using a “shallow subsurface connection” as a basis for determining that a water is adjacent to, e.g., waters that are navigable in fact, and therefore subject to CWA jurisdiction.[46]


With the lower courts divided, no Supreme Court decision on point, and a Clean Water Rule that largely avoids the issue, the question of whether the CWA regulates the discharge of pollutants to hydrologically connected groundwater will likely remain hotly contested. Until this question is resolved, regulators and regulated parties alike will face some degree of uncertainty, and the risks and costs that inevitably accompany it.

That said, this uncertainty is not boundless. Even under the rules advanced by cases such as Yadkin Riverkeeper, Sierra Club and Hawai‘i Wildlife Fund, not all groundwater discharges will implicate the CWA. The plaintiffs in those cases either alleged or proved an actual, significant connection between groundwater discharges and surface-water pollution. Thus, the existence of a theoretical connection between groundwater and surface water is very likely insufficient to establish CWA jurisdiction even under these cases. At the same time, neither does the rule of Village of Oconomowoc Lake and Cape Fear River Watch mean parties will be free to discharge pollutants into groundwater as they please. Quite apart from the CWA, state and tribal laws still regulate discharges to groundwater,[47] as does the Safe Drinking Water Act.[48] The Resource Conservation and Recovery Act[49] and the Comprehensive Environmental Response, Compensation and Liability Act[50] serve as additional safeguards.

The Fourth and Ninth Circuits may soon have the opportunity to address head on whether the CWA reaches discharges to hydrologically connected groundwater. The defendants in Yadkin Riverkeeper[51]and Sierra Club[52] both recently filed motions to certify the trial courts’ decisions with respect to groundwater for interlocutory appeal to the Fourth Circuit. Hawai‘i Wildlife Fund is currently before the Ninth Circuit.[53] Rulings on the merits in these cases should help clarify the reach of the CWA, whether by moving toward a national consensus or creating a circuit split that might get the attention of the Supreme Court.

In the meantime, though, it is likely that CWA citizen suits will continue to include claims related to groundwater contamination.[54]

For more information please contact any member of Marten Law’s Water Quality team.

[1] 33 U.S.C. §§ 1311(a), 1362(12)(A), 1362(7).

[2] Id. § 1342.

[3] J. Kray, “Clean Water Act: ‘Waters of the United States’ Rule Faces Political, Legislative, and Legal Challenges,” Marten Law Environmental News (June 3, 2015).

[4] 33 U.S.C. § 1311(a).

[5] Id. § 1362(7), (12).

[6] Id. § 1362(14).

[7] See id. § 1342(a)-(b).

[8] Id. § 1365.

[9] Clean Water Rule: Definition of “Waters of the United States,” 80 Fed. Reg. 37054, 37099 (June 29, 2015). However, there have been calls for EPA and the Army Corps of Engineers to regulate groundwater under the CWA. See, e.g., id. at 37064-65 (discussing Science Advisory Board’s position that “‘[t]he Clean Water Act exclusions of groundwater and certain other exclusions listed in the proposed rule and the current regulation do not have scientific justification”).

[10] No. 1:14-CV-753, 2015 WL 6157706 (M.D.N.C. Oct. 20, 2015)

[11] Id. at *2.

[12] Id. at *3.

[13] Id. at *8.

[14] Id.

[15] Id.

[16] Id. at *9-10.

[17] 24 F. Supp. 3d 980 (D. Haw. 2014).

[18] Id. at *10 (quoting N. Cal. River Watch v. Mercer Fraser Co., No. C–04–4620 SC, 2005 WL 2122052, at *2 (N.D.Cal. Sept. 1, 2005)).

[19] Id. at *10 (citing 56 Fed.Reg. 64,876, 64,892 (Dec. 12, 1991); 66 Fed.Reg. 2960, 3015 (Jan. 12, 2001); 73 Fed.Reg. 70,418, 70,420 (Nov. 20, 2008)).

[20] No. 2:15CV112, 2015 WL 6830301 (E.D. Va. Nov. 6, 2015).

[21] Id. at *1.

[22] Id. at *5.

[23] Id.

[24] Id. at *6.

[25] No. CV 11-5885, 2015 WL 5013729 (E.D. Pa. Aug. 24, 2015).

[26] Id. at *1.

[27] Id. at *3.

[28] Id.

[29] Id. at *28.

[30] Id.

[31] Id. at *28-30.

[32] Id. at *34 n. 43 (citing Calif. Sportfishing Protection Alliance v. Diablo Grande, Inc., 209 F.Supp.2d 1059, 1076 n.8 (E.D.Cal.2002); Idaho Rural Council v. Bosma, 143 F.Supp.2d 1169, 1180 (D.Idaho 2001);Village of Oconomowoc Lake, 24 F.3d 962; Town of Norfolk v. U.S. Army Corps of Eng'rs, 968 F.2d 1438, 1451 (1st Cir.1992)).

[33] See generally Allison L. Kvien, Note, Is Groundwater that is Hydrologically Connected to Navigable Waters Covered Under the CWA?: Three Theories of Coverage and Alternative Remedies for Groundwater Pollution, 16:2 Minn. J.L. Sci. & Tech., 957, 977-978, 1001-1010 (2015) (collecting cases). The Second Circuit has also indicated some support for this view of CWA jurisdiction. See Waterkeeper All., Inc. v. U.S. E.P.A., 399 F.3d 486, 514-15, 514n.26 (2d Cir. 2005) (upholding EPA decision to regulate discharges from confined animal feeding operations into groundwater, if at all, on a case-by-case basis and finding that “[t]he EPA did not, in other words, mean to suggest that NPDES authorities lacked the power to impose groundwater-related requirements on a case-by-case basis, where necessary”). However, in a subsequent decision, without deciding the issue the Second Circuit acknowledged Rice and Village of Oconomowoc Lake as authority that the CWA does not apply to groundwater contamination. Cordiano v. Metacon Gun Club, Inc., 575 F.3d 199, 223 (2d Cir. 2009).

[34] More specifically, many courts—including Yadkin Riverkeeper, Sierra Club and Hawai‘i Wildlife Fund—describe groundwater as a conduit through which contaminants reach jurisdictional waters. See, e.g., Hawai"i Wildlife Fund, 24 F. Supp. 3d at 995 (“There is nothing inherent about groundwater conveyances and surface water conveyances that requires distinguishing between these conduits under the Clean Water Act. When either type of waterway is a conduit through which pollutants reach the ocean, then there has been the ‘addition of [a] pollutant to navigable waters.’”). Other courts have described groundwater as a “point source” for CWA purposes. See, e.g., Raritan Baykeeper, Inc. v. NL Indus., Inc., No. 09-4117, 2013 WL 103880, at *15 (D.N.J. Jan. 8, 2013).

[35] 24 F.3d 962, 965 (7th Cir. 1994).

[36] 250 F.3d 264, 269 (5th Cir. 2001).

[37] 437 F.3d 157, 161 (1st Cir. 2006) (“The CWA does not cover any type of ground water; the CWA covers only surface water.”) vacated on other grounds by 467 F.3d 56 (1st Cir. 2006).

[38] Hawai‘i Wildlife Fund, 24 F. Supp. 3d at 996; Yadkin Riverkeeper, 2015 WL 6157706 at *10.

[39] 25 F. Supp. 3d 798, 800 (E.D.N.C. 2014) amended, No. 7:13-CV-200-FL, 2014 WL 10991530 (E.D.N.C. Aug. 1, 2014).

[40] Id. at 809-10.

[41] Id. at 810.

[42] See, e.g., Patterson Farm, Inc. v. City of Britton, S.D., 1998 DSD 34, ¶ 17, 22 F. Supp. 2d 1085, 1091 (D.S.D. 1998) (citing Village of Oconomowoc Lake and holding that in light of that and other cases, “this Court lacks subject matter jurisdiction over plaintiff's claim that the poor operation and maintenance of the industrial lagoons is causing discharges into the groundwater … [e]ven if plaintiff [had] alleged that the discharges were migrating to surface water”); Kelley for & on Behalf of People of State of Mich. v. United States, 618 F. Supp. 1103, 1107 (W.D. Mich. 1985) (rejecting CWA claim where plaintiff alleged defendant responsible for contaminating groundwater that discharged into navigable waters and holding that “Congress did not intend the Clean Water Act to extend federal regulatory and enforcement authority over groundwater contamination”).

[43] See 80 Fed. Reg. at 37073, 37099.

[44] 40 CFR 230.3(o)(2).

[45] 80 Fed. Reg. at 37099.

[46] See id. at 37083.

[47] Id. at 37060 (“Many states and tribes, for example, regulate groundwater.”).

[48] 42 U.S.C. §300f et seq.

[49] 42 U.S.C. § 6901 et seq.

[50] 42 U.S.C. § 9601 et seq.

[51] No. 1:14-CV-753, Dkt. No. 58 (M.D.N.C. filed Nov. 25, 2015).

[52] No. 2:15CV112, Dkt. No. 68 (E.D. Va. filed Jan. 07, 2016).

[53] No. 15-17447 (9th Cir. filed December 15, 2015).

[54] See, e.g., Press Release, “TVA may face a third lawsuit over toxic coal ash leaking into Cumberland River,” (Jan 14, 2016) (announcing Sierra Club notice of intent to sue Tennessee Valley Authority for CWA violations stemming from, inter alia, groundwater contamination).


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