Without substantial adaptation that addresses projected wastewater management challenges and community needs (Section 4.2.6.1; Kirshen et al., 2018; Kirchhoff and Watson, 2019; Kool et al., 2020; Nazarnia et al., 2020; Hughes et al., 2021), coastal water quality in many areas will decrease because of more frequent or severe releases of untreated wastes (high confidence) (Flood and Cahoon, 2011; Hummel et al., 2018; Hughes et al., 2021; McKenzie et al., 2021b), and this will have harmful consequences for human and coastal ecosystem health