January 10, 2013

U.S. Supreme Court Reaffirms Settled Precedent for Regulating Transfers of Water Through Stormwater Systems and Other Water Infrastructure

Ruling Provides Greater Clarity for Clean Water Act Compliance
Holland & Knight Alert
Amy L. Edwards

On January 8, 2013, the U.S. Supreme Court unanimously overturned a judgment of the U.S. Court of Appeals for the Ninth Circuit that would have had vast consequences for stormwater systems and other water infrastructure across the country.

In Los Angeles County Flood Control District v. Natural Resources Defense Council, Inc., the Court held that "the flow of water from an improved portion of a navigable waterway into an unimproved portion of the very same waterway does not qualify as a discharge of pollutants" under the Clean Water Act.1 By overturning the Ninth Circuit’s ruling that the flood control district had violated its stormwater permit, the Justices awarded an important victory to Los Angeles County.


In many areas, stormwater, snow melt and other runoff from various non-point sources is conveyed through a municipal separate storm sewer system (MS4) before being discharged into navigable waters that are regulated subject to the Clean Water Act. Because such runoff is often polluted, every MS4 serving a population of at least 100,000 people must obtain a National Pollutant Discharge Elimination System (NPDES) permit, which limits the quantity of specified pollutants that can be discharged via the MS4.2

In this case, the Los Angeles Flood Control District (District) has operated its MS4 under an NPDES permit since 1990.3 The Natural Resources Defense Council and Santa Monica Baykeeper filed a citizen suit, claiming that the District had failed to comply with the water quality standards mandated by its MS4 permit, based on data from monitoring stations in the Los Angeles and San Gabriel Rivers.4The district court dismissed these claims, finding that because the water quality monitors measured stormwater combined from multiple sources, including but not limited to the District’s MS4, there was insufficient evidence that the District had definitely violated the terms of its permit.5However, the Ninth Circuit reversed the district court’s ruling, reasoning that the stormwater was “discharged” when it passed from concrete channels to unimproved portions of both rivers. Because the District controlled the improved portion of the rivers, the Ninth Circuit held that it alone had discharged the water.6

The Court's Decision

In its opinion, the Supreme Court flatly rejected the Ninth Circuit’s reasoning. The specific issue before the court was whether a discharge of pollutants occurs when polluted water flows from one portion of a navigable water of the United States, through a concrete channel or other engineered improvement, into a lower portion of the same river. Based on well-settled precedent, the Court’s answer to this question was clearly no.

In arriving at its decision, the Court relied on its 2004 opinion in South Florida Water Management District v. Miccosukee Tribe of Indians, in which it held that the transfer of polluted water between two parts of the same water body did not constitute a discharge of pollutants under the Clean Water Act.7

In Miccosukee, the polluted water was removed from a canal, transported through a pump station and then deposited into a nearby reservoir.8 The Court held that this water transfer would count as a discharge of pollutants under the CWA only if the canal and the reservoir were "meaningfully distinct water bodies," relying on the reasoning that a "discharge" of a pollutant into a water body requires that pollutant to be added to that water body, and that no pollutant is added when already-polluted water is merely transferred from one location to another. To support this reasoning, the Court cited the Miccosukee Court's analogy that "if one takes a ladle of soup from a pot, lifts it above the pot and pours it back into the pot, one has not 'added' soup or anything else to the pot."9 Finding that reasoning to be equally applicable in this case, the Court stated "it follows, a fortiori, from Miccosukee that no discharge of pollutants occurs when water, rather than being removed and then returned to a water body, simply flows from one portion of the water body to another."10 As a result, Court reversed the Ninth Circuit’s judgment.

Interestingly, the Court also flatly rejected NRDC's alternative argument for upholding the Ninth Circuit's ruling, which it had raised for the first time in its reply brief. The NRDC had argued that "the Court of Appeals reached the right result albeit for the wrong reason," because "the monitoring system proposed by the District and written into its permit showed numerous instances in which water quality's standards were exceeded," which therefore was "sufficient to establish the District's liability under the CWA for upstream discharges." In a direct rebuke of NRDC, the Court expressly refused to address this alternative argument because "it is not embraced within, or even touched by, the narrow question on which we granted certiorari."11


In reaffirming its Miccosukee decision, the Court further clarified that the mere movement of water through an engineered structure within a single navigable water cannot constitute the "addition" of a pollutant. Indeed, the implications of this decision extend far beyond Los Angeles County's MS4 system.

The decision averts what could have been potentially disastrous consequences for thousands of engineered water management systems across the country, including MS4s, dams and flood control systems, ecosystem preservation projects, and irrigation and drinking water supply networks, some of which convey crucial water supplies over long distances to meet important public needs. Had the Ninth Circuit’s decision been upheld, movement of water though any one of myriad in-stream structures would have required a Clean Water Act NPDES permit. This new level of regulation would have been particularly onerous for authorities charged with transferring significant amounts of water over long distances to meet critical public needs. Instead, by reversing the Ninth Circuit, the Supreme Court upheld existing precedent and provided managers of such water transfers systems with greater degree of clarity and stability in the Clean Water Act’s regulatory landscape. 


1 Los Angeles County Flood Control Dist. v. Natural Res. Def. Council, Inc., No. 11-460, slip op. at 4 (U.S. Jan. 8, 2013) (hereinafter, LA Flood Control Dist. V. NRDC).

2 See id. at 2.

3 See id.

4 See id.

5 See id.

6 See id. at 3.

7 541 U.S. 95, 109-112 (2004).

8 See id. at 100.

9 Id. at 109-10.

10 LA Flood Control Dist. V. NRDC, supra note 1, at 4.

11 Id. at 5.

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