Background

Urban storm water runoff has been recognized as one of the most significant sources of water pollution in the country.  The problem is particularly acute in Los Angeles County, which operates a massive municipal storm water system consisting of approximately 500 miles of open channels and 2,800 miles of storm drains.  This system collects and then discharges urban storm water runoff into various navigable rivers, which in turn flow into the Santa Monica Bay and the Pacific Ocean. 

The system is governed by a regional storm water permit covering the county and the 84 incorporated cities within the county’s Flood Control District.  Among other requirements, the permit mandates monitoring of mass-emissions downstream of outfall points in the Los Angeles and San Gabriel Rivers.  This monitoring measures all of the constituents of concern that are present in the water, thereby giving a cumulative picture of the pollutant load in the water body. 

The case arose out of allegations by environmental organizations that the county’s annual monitoring reports showed more than 100 violations of the regional storm water permit occurring between 2002 and 2008.  The thrust of the plaintiffs’ argument was that the monitoring data, which showed undisputed exceedances of permit limits at the mass-emissions monitoring stations, conclusively established the county’s liability for violations of the permit. 

In a 2011 opinion, the U.S. Court of Appeals for the Ninth Circuit rejected the claim that the monitoring data - in and of itself - conclusively established the county’s liability.  The opinion reasoned that the data did not show that the county itself actually contributed to the measured permit violations.  Nonetheless, the Ninth Circuit held that the county was liable on another theory.  Under this line of reasoning, when the storm water flowed from concrete channels operated by the county into the navigable waters, the county was discharging from a point source in violation of the permit limitations.

But the Supreme Court granted certiorari and in January 2013 reversed the Ninth Circuit.  Los Angeles County Flood Control Dist. v. Natural Resources Defense Council, 133 S. Ct. 710 (2013). 

The Supreme Court Weighs In, Ninth Circuit Reacts

The Supreme Court concluded there is no point-source discharge when polluted storm water flows from a navigable part of a river, through county-operated concrete channels or other engineered improvements, into another navigable portion of the same river.  The Court did not address any other basis of potential liability and it remanded the case to the Ninth Circuit for further proceedings.

On August 8, 2013, the Ninth Circuit issued its opinion on remand.  In finding that the county and the Flood Control District were liable for violating the regional storm water permit, the court abandoned the reasoning in its 2011 decision and this time agreed with the argument advanced by the environmental groups that the annual monitoring data conclusively established liability. 

In reaching this holding, the court rejected the county’s claims that the mass-emission monitoring data was not intended to define compliance with the permit.  The court found that the plain language of the permit provided otherwise.  Specifically, the court reasoned that: (1) the permit establishes a Monitoring and Reporting Program that characterizes and assesses compliance with the applicable water quality standards, and (2) the provisions limiting the permittee’s responsibility to the discharges for which it is the operator applied only to the appropriate remedy for permit violations, not the liability for those violations in the first instance. 

Additionally, the Ninth Circuit pointed to several extrinsic factors in support of its decision.  First, the court pointed to the language in the Clean Water Act regulations requiring every permittee to monitor its discharges into the navigable waters in a manner sufficient to determine whether it is in compliance.  Second, the court emphasized that the Los Angeles Regional Quality Control Board, the agency charged with issuing and implementing the regional storm water permit, had expressly rejected the county’s position in a nearly identical lawsuit. Finally, the court explained that the Clean Water Act, as evidenced by its legislative history, relies heavily on self-monitoring to achieve its fundamental purpose of reducing water pollution.

Complexities of Regulating Municipal Storm Water Systems

The court acknowledged that regulating pollution from a large municipal storm water system is “substantially more complicated than regulating pollution from a few defined point sources.”  But the court also found that the Clean Water Act gave the permitting authorities broad discretion in how to address this complexity.  And it also emphasized that nothing in the storm water permitting scheme under the Act relieved permittees, such as the county, of their obligation to monitor and maintain compliance with their permits.