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Ninth Circuit Holds that Use of Groundwater Injection Wells Required Clean Water Act NPDES Permit

The Ninth Circuit Court of Appeals has ruled that groundwater injection wells may result in an “indirect” discharge of pollutants to navigable waters of the United States, that requiring a permit under the federal Clean Water Act (CWA). The case involved groundwater injection wells operated by the County of Maui that discharged effluent into groundwater near the coastline. The effluent reached the Pacific Ocean through submarine springs. The court ruled the permit requirements of the CWA applied, even though the county did not discharge effluent directly to the ocean, because the wells were a point source, pollutants were “fairly traceable” from the wells to the ocean, and the pollutant levels reaching the ocean were “more than de minimus.” [Hawai’i Wildlife Fund et al. v. County of Maui ___F.3d___, Case No. 15-17447, (9th Cir. Feb. 1, 2018). ]



The CWA prohibits the “discharge of any pollutant by any person,” 33 U.S.C. §1311(a), and defines “discharge of a pollutant” as “any addition of any pollutant to navigable waters from any point source,” id. § 1361(12). A “point source” is:

. . .any discernible, confined and discrete conveyance, including but not limited to any . . . well . . . from which pollutants are or may be discharged. Id. § 1361(14).

A party who obtains an National Pollutant Discharge Elimination System (NPDES) permit is exempt from the general prohibition on point source pollution. Id. §§ 1311(a), 1342(a)(1).

The County of Maui operates a wastewater treatment plant near Lahaina in west Maui. After treatment, wastewater is either sold to customers for irrigation uses or injected into groundwater wells for disposal. A portion of the injected effluent enters the Pacific Ocean through the groundwater. Tracer dye studies indicated that it emerges into the ocean from submarine springs located about one-half mile from the county’s facility.

At the time it built the facility the county considered building an outfall, but concluded direct discharges would be “too harmful to the coastal waters,” and opted instead for injection wells. The county did not obtain an NPDES permit for its disposal using injection wells.

Three non-governmental organizations brought suit against the county under the CWA, contending the county’s discharges were unlawful absent an NPDES permit. The U.S. District Court agreed, on three independent grounds: 1) the county “indirectly discharge[d] a pollutant into the ocean through a groundwater conduit,” 2) the groundwater is a “point source” under the CWA, and 3) the groundwater is a “navigable water” under the CWA. Haw. Wildlife Fund v. County Of Maui, 24 F.Supp.3d 980, 993, 999, 1005 (D. Haw. 2014). In addition, the District Court rejected an argument by the county that the CWA did not provide fair notice that its discharges to groundwater were prohibited.


The Ninth Circuit’s Decision

The Ninth Circuit agreed with the District Court that the county’s discharges are regulated under the CWA. The Ninth Circuit expressly “assume[d] without deciding” that the groundwater was neither a point source nor a navigable water under the CWA. It agreed with the District Court that the county had fair notice that its actions could violate the CWA.

The parties agreed that the county’s wells were a “point source,” and that pollutants injected into the wells ultimately reached navigable waters, the Pacific Ocean.

In finding that the county’s actions were a point source discharge of a pollutant subject to the CWA, the court contrasted the county’s actions with non-point source discharges. Citing its decision in Ecological Rights Found. v. Pacific Gas & Electric Co., 713 F.3d 502 (9th Cir. 2013), the court explained non-point source pollution “arises from many different sources,” from “dispersed activities,” is “not traceable to any single discrete source,” and is very difficult to regulate through individual permits. In contrast, the county here operated four identified wells, the pollutants entering the ocean were traceable to its wells, and the wells could be regulated through individual permits.


Indirect Discharge Argument

The Ninth Circuit rejected the county’s argument that under the CWA the point source itself, here the wells, must discharge directly into navigable waters. For this conclusion the court cited cases holding the CWA applied were there was some collection or confinement of the pollutants before they entered navigable waters, e.g. pollutants collected in a stormwater drain system, even though the collected pollutants were not discharged directly into navigable waters. The court held:

. . .the county liable under the CWA because (1) the county discharged pollutants from a point source, (2) the pollutants are fairly traceable from the point source to a navigable water such that the discharge is the functional equivalent of a discharge into the navigable water, and (3) the pollutant levels reaching navigable water are more than de minimis.


‘Direct Hydrological Connection’ Standard Not Adopted By the Court

The Ninth Circuit declined to adopt a “direct hydrological connection” standard proposed by the U.S. Environmental Protection Agency (EPA) in an amicus brief, finding it was not supported by the text of the CWA. The court likewise disagreed with the District Court’s view that liability attaches under the CWA whenever pollutants reach navigable waters, “regardless of how they get there.” It explained that liability attached in this case because the evidence “clearly connect[ed] all four wells’ discharges to the consistently emerging pollutants in the ocean.” The Ninth Circuit “left for another day” the task of determining:

. . .when, if ever, the connection between a point source and a navigable water is too tenuous to support liability under the CWA.

Nor did it adopt the District Court’s alternative rationales that the groundwater was a “point source” or a navigable water under the CWA.


Conclusion and Implications

In Hawai’i Wildlife Fund the Ninth Circuit joined several other Circuits in concluding that an “indirect discharge” to navigable waters may be subject to the CWA. Where to draw the line, i.e., when is the connection “too tenuous” to support liability, will doubtless be the subject of future cases. The court’s reasoning suggests that in those future cases the parties will likely argue over whether the activity at issue is more like a point source or a non-point source discharge.

The ruling in Hawai’i Wildlife Fund may give pause to parties pursuing projects that gather stormwater, for example, for injection or infiltration into groundwater. Such projects are widely seen as providing multiple benefits, controlling runoff while enhancing groundwater supplies. If the receiving groundwater aquifer has a sufficient connection to surface waters, however, that will raise concerns about potential permitting requirements under the CWA.

Various amici are likely disappointed that the Ninth Circuit did not address the District Court’s alternative rationales that the groundwater itself is a “point source” or a navigable water under the CWA. Those issues, too, will likely resurface in future cases. The court’s opinion is available online at:

(Dan O’Hanlon)