Abstract
The COVID-19 pandemic accelerated global adoption of wastewater and environmental surveillance (WES) and revealed its value as a complement to case-based infectious disease monitoring. However, practical scientific, ethical, and legal standards for public health implementation remain limited. To address this gap, the Public Health Alliance for Genomic Epidemiology (PHA4GE) established a multidisciplinary international working group to develop community-driven, open guidance on WES methods and best practices. By integrating expertise from public health researchers, practitioners, bioethicists, and legal scholars, together with feedback from the broader public health community, these standards aim to promote transparent, reproducible, and accessible implementation of WES worldwide. This continuously updated framework spans surveillance strategies, data analysis, data sharing, and ethical-legal considerations, aligning with normative guidance from global public health authorities while remaining adaptable to diverse contexts and resource levels. All guidance documents can be found at https://pha4ge.github.io/wastewater-guidance.