Barry Law Environmental and Earth Law Journal

November 25, 2025

For a long time, the people of the United States relied on the idea that correctly lined landfills and wastewater facilities operating in accordance with their permits would minimize contamination risks. That assumption has not aged well. Now, modern science paints a different picture. Landfills generate complex chemical mixtures, liners slowly degrade, and wastewater treatment plants cannot reliably remove many of the pollutants we now know are widespread. PFAS, pharmaceuticals, solvents, and tiny plastic fragments travel through groundwater and surface water in ways that older environmental laws never fully anticipated.

This tension has slowly pushed the Resource Conservation and Recovery Act (RCRA) and the Clean Water Act (CWA) into overlapping territory. The Supreme Court’s decision in County of Maui v. Hawaii Wildlife Fund added even more pressure by opening the door to liability for pollutants that move through groundwater before reaching navigable waters. These developments have forced regulators, courts, and facility operators to rethink long-held assumptions about where waste ends and water pollution begins.

RCRA and the Broad Idea of “Solid Waste”

RCRA defines “solid waste” as “covering garbage, sludge, and many other discarded materials, regardless of whether they are actually ‘solid.’” [1] RCRA is intended to prevent environmental harm before it occurs, not mop up damage afterward. [2] Even so, the statute struggles to keep pace with contaminants like PFAS. PFAS are slow-degrading chemicals often detected in wastewater facilities, and their adverse health effects include decreased fertility, cancer risks, and developmental delays in children. [3] Since these chemicals have not been

formally listed as hazardous waste and do not fit neatly into characteristic-waste categories, regulators often rely on RCRA’s “imminent and substantial endangerment” clause as a backstop. [4] [5] This workaround highlights the gap between emerging science and regulatory classifications that were created nearly half a century ago.

The Clean Water Act and the Wastewater System

The Clean Water Act takes a different approach. Pollutant discharge is prohibited from a point source to navigable waters unless the discharger holds an NPDES permit.[6] [7] [8] For a long time, indirect discharges, pollutants seeping into groundwater and eventually migrating to rivers or lakes, fell outside that requirement. The Maui ruling revised how people thought about indirect discharges. In 2020, the Supreme Court concluded that when pollution moves through groundwater in a manner that closely mimics direct discharge, the source may still need an NPDES permit. [9] Due to this ruling, operators of landfills, sewage systems, and industrial impoundments must now consider not only what leaves a pipe, but also what leaks, migrates, or slowly percolates underground.

PFAS in Landfill Leachate and Wastewater

Scientific studies have shown that landfills play a significant role in the spread of PFAS. When wastewater treatment plants take in this leachate, most PFAS pass through essentially unchanged. [10] They end up in surface waters or in biosolids that are applied to agricultural land. The U.S. Environmental Protection Agency (EPA) has offered interim guidance. However, it has not yet issued PFAS-specific disposal or treatment rules under RCRA or the CWA. [11] States, such as Maine and Michigan, have filled this regulatory void with their own rules for PFAS-contaminated sludge. . [12] [13]This patchwork response illustrates how quickly state policy can move when federal regulation lags.

Conclusion

Congress developed waste and water laws under the notion that they would not intermingle, but the contaminants do not behave that way. Leachate moves into groundwater. Groundwater moves into streams. Wastewater plants receive waste they are not designed to handle. The legal system is adjusting, but the pace is slow compared to the spread of contaminants. Solid waste and wastewater management have graduated from a local issue to an emerging national challenge. Updating the regulatory framework now may be the only way to prevent a more serious drinking-water crisis in the years ahead.

Written by D’Andra McFarlane, Associate Editor 2025-2026