On February 1, 2018, the United States Court of Appeals for the Ninth Circuit held that a pollutant need not be discharged from a point source directly  into navigable water to be subject to NPDES permitting requirements and that therefore Clean Water Act liability can attach to point source discharges through groundwater to navigable water.

The dispute in Hawai‘i Wildlife Fund v. County of Maui involved 4 wells that discharge 3 to 5 million gallons of treated effluent from the County of Maui into the groundwater each day.  A “tracer dye” study conducted by the EPA confirmed that at least some of this treated effluent travels through the groundwater and ultimately reaches the Pacific Ocean.  The County argued unsuccessfully that these discharges do not require a NPDES permit because they do not convey pollutants directly  to navigable water.

The Ninth Circuit held that a discharge to groundwater is subject to NPDES permitting requirements when 1) there is a discharge of pollutants from a point source, 2) the pollutants are “fairly traceable” from the point source to the navigable water, and 3) more than a de minimis level of pollutants reaches the navigable water.  Significantly, the court rejected the rule proposed by the U.S. EPA as amicus curiae, which would have required a “direct hydrological connection” between the groundwater and the navigable water.  Unfortunately, the court declined to decide “when, if ever, the connection between a point source and a navigable water is too tenuous to support liability under the CWA,” leaving this question to be litigated another day.

In its decision, the Ninth Circuit looked to cases out of both the Second and Fifth Circuits.  Specifically, it referenced Concerned Area Residents for the Environment v. Southview Farm, a case in which the Second Circuit held that NPDES permitting requirements apply to liquid manure that is collected in tankers, discharged onto fields, and flows over the fields and into navigable water.  Additionally, it cited a Fifth Circuit case, Sierra Club v. Abston Construction, which involved the discharge of sediments that were collected in basins and carried “by gravity flow of rainwater” into navigable waters.  The Ninth Circuit reasoned that the wells at issue were analogous to the point sources in Abston and Southview Farm because they “discretely collect and convey” the effluent to navigable water, even though the effluent happens to travel through groundwater first.

In addition to citing cases from other circuits, the court considered Justice Scalia’s plurality opinion in Rapanos v. United States  “for its persuasive value.”  In Rapanos, Justice Scalia acknowledged that the CWA does not prohibit the “‘addition of any pollutant directly to navigable waters from any point source,’ but rather the ‘addition of any pollutant to  navigable waters.’”  The court found that the County’s position was not only at odds with Scalia’s plurality opinion but also strayed from the plain language of the CWA by reading the word “directly” into the statute.

Finally, the court rejected the County’s argument that it lacked fair notice that its actions were prohibited by the CWA and, therefore, that enforcement of CWA would violate due process.  The County contended that it lacked such notice because the CWA could be fairly read to exclude the County’s wells from the NPDES permitting requirements.  The court disagreed, finding that a reasonable person would have understood the CWA to prohibit the County’s actions, which fell “squarely within” the CWA’s plain language.

The tone of the court’s rather firm ruling was captured in its conclusion, when it stated that its decision will prevent the County “from doing indirectly that which it cannot do directly.”