The Ninth Circuit recently issued a decision in Cal. River Watch v. City of Vacaville (Case No. 20-16605) (“Vacaville”) regarding the breadth of Resource Conservation and Recovery Act (“RCRA”) liability for contributing to the transportation of a solid waste, which may present an “imminent and substantial endangerment” to health or the environment. (42 U.S.C. § 6972(a)(1)(B).) Ultimately, the Ninth Circuit found that because the City of Vacaville (“City”) transported through its water distribution system drinking water that contained discarded hexavalent chromium from activity unassociated with the City, a triable issue existed regarding whether the City was liable under the “substantial endangerment” provision of RCRA, despite the City’s lack of involvement in generating the waste in question or in the waste disposal process. The decision appears to significantly undercut Hinds Investments, L.P. v. Angioli, 654 F.3d 846 (9th Cir. 2011) (“Hinds”), which held that some involvement in the waste disposal process is necessary for liability to exist under RCRA’s imminent and substantial endangerment liability provision, and could have wide-raging implications for California municipalities and public water system operators. This case could be especially problematic given the recent federal and State focus on perfluoroalkylated substances (“PFAS”), which are found in a wide variety of products (including pots, pans, clothing, food service items, among others), and can be released into the environment through a number of activities, including, but not limited to domestic household tasks, such as washing clothes and dishes.