1. Connor, R. et al. The United Nations World Water Development Report (United Nations, 2017).
2. Municipal wastewater systems in Canada, 2013 to 2017 Vol. 11-627-M (Statistics Canada, 2019).
3. Sterling, S. M., Ducharne, A. & Polcher, J. Nat. Clim. Change 3, 385–390 (2013).
4. Cooley, S. W., Ryan, J. C. & Smith, L. C. Nature 591, 78–81 (2021).
5. Progress on Wastewater Treatment (UN, 2021); https://unhabitat.org/sites/default/files/2021/08/sdg6_indicator_report_631_progress_on_wastewater_treatment_2021_english_pages.pdf