In a 6-3 decision written by Justice Steven Breyer, the United States Supreme Court rejected an Interpretive Statement issued by the Environmental Protection Agency ("EPA") in 2019, which stated that “all releases to groundwater … are excluded from permitting” requirements under the Clean Water Act ("CWA"). The Maui County v. Hawai’i Wildlife Fund decision involved effluent from a wastewater treatment plant that was injected into four wells and eventually made its way through groundwater into the Pacific Ocean.
Environmental groups filed a citizens’ suit complaint under the CWA alleging that the wastewater effluent injected into four wells on the island was moving through ground water and was being discharged into the Pacific Ocean. They alleged that under the
National Pollutant Discharge Elimination System (“NPDES”) program, the County was required to obtain an NPDES permit before discharging those pollutants to navigable waters. The County argued that all pollutants discharged to groundwater do not require an NPDES permit, since there is not a “direct” discharge of the pollutants to navigable waters.
The District Court found that the discharge was “functionally one into navigable waters,” and found in favor of the environmental groups. At the Ninth Circuit Court of Appeals, the Court affirmed the District Court decision, but applied a different standard, stating that an NPDES permit was required when “pollutants are fairly traceable from the point source to a navigable water.” The case then went to the United States Supreme Court for review. The Solicitor General filed an amicus brief in support of the County, arguing
that a new Interpretive Statement issued by the EPA determined that all releases to ground water are excluded from the NPDES permitting requirements.
In its landmark decision, the Supreme Court found that an NPDES permit is required when there is a direct discharge from a point source to navigable waters or “when there is a functional equivalent of a direct discharge,” and remanded the case back to the lower court to evaluate the facts in light of this standard. The Court rejected the Ninth Circuit standard as overly broad, and the County’s position as overly narrow. In reaching this decision, the Court acknowledged that a “more absolute position” such as advocated by the Administration, “may be easier to administer,” but it would be inconsistent with the objectives of the CWA.
In establishing the “functional equivalent” standard, the Court identified
several factors that are to guide the lower courts in determining whether a permit is required. The most important factors are the time of travel through the groundwater and the distance traveled. Unfortunately, the examples given by the Court do not provide much guidance to the state permitting agencies or the courts.
The Court described the obvious example of pollutants that take decades to travel through groundwater to navigable waters and do not require a permit contrasted with a discharge though a few feet of groundwater (or across a beach) which would require a permit. The Court also noted that the material through which the pollutant travels and the extent to which the pollutant is diluted or chemically changed as it travels through the groundwater are key factors in determining
whether the discharge is functionally equivalent to a direct discharge to navigable waters, though it gave no examples of the materials it had in mind. Significantly, the Court stated that it anticipates that additional guidance would be developed through decisions in individual cases over time. In short, this is not a bright-line test, and the factors to be evaluated will be specific to each situation.
Because there is not a bright line test, any entity with an injection well or other means by which pollutants connect or could connect to groundwater that connects to navigable waters should evaluate their situation to determine if they could be required to obtain an NPDES discharge permit. For example, a surface impoundment which is connected to groundwater (through a leak or simply an unlined impoundment) could have a connection to navigable waters. If the navigable waters are
near enough to the impoundment and the time of travel from the impoundment through the groundwater to the navigable waters is short enough, it is possible that an aggressive regulator could try to require a discharge permit. While we would not anticipate that a regulator would take this position at present, this decision could provide a path to such a course of action.