On May 21, 2018, WLF filed formal comments with the Environmental Protection Agency (EPA), urging it to faithfully adhere to the statutory limits of federal-permitting jurisdiction under the Clean Water Act. Addressing whether pollutant discharges from point sources that reach navigable waters through groundwater are subject to CWA regulation, WLF’s comments advance two main points. First, because groundwater is neither a “navigable water” nor a “source point” under the CWA, EPA has no regulatory jurisdiction over groundwater pollutants. Second, WLF reminds the EPA that States already exercise regulatory jurisdiction over groundwater under the CWA’s established scheme of cooperative federalism. WLF encouraged EPA to explicitly clarify that the CWA’s statutory language cannot be construed in a way that eviscerates those important jurisdictional limits.