Per- and polyfluoroalkyl substances (PFAS) are compounds of emerging concern based on ubiquitous distribution and potential human health impacts. Whereas manufacturing plants and fire-training/suppression areas are recognized as primary sources of PFAS contamination of the environment, understanding the role of water treatment plants (WTPs) and water resource recovery facilities (WRRFs) in PFAS cycling is important. Literature on the presence and pathways of PFAS within and between WTPs and WRRFs was reviewed and synthesized to address this knowledge gap. The production, use, and disposal of PFAS was connected to the water cycle via aquifers/surface water/sediment, drinking water treatment, domestic/industrial water use, domestic/industrial wastewater treatment, the atmosphere, land application, landfills, thermal treatment of wastes, and food production. WTP and WRRF flows release PFAS in liquid-phase, solid-phase, and gas-phase matrices. The purpose of this review is to educate and inform readers of the fate and transport of PFASs throughout the urban water cycle emphasizing the WTP–WRRF connection. Source reduction programs, treatments that interrupt the PFAS cycle, and comprehensive analytical methods are future research needs. DOI: 10.1061/(ASCE)EE.1943-7870.0001943. This work is made available under the terms of the Creative Commons Attribution 4.0 International license, https://creativecommons.org/licenses/by/4.0/.
