Wastewater surveillance is a valuable and noninvasive way to detect, monitor and rule out viral pathogen transmission at the population level. Drawing on lessons learned from severe acute respiratory virus two (SARS-CoV-2), monkeypox virus, norovirus and influenza A viruses, we outline six key considerations for designing or refining a wastewater surveillance program for a viral pathogen: pathogen suitability, surveillance objective, sampling strategy, molecular assays, data transformation, and analysis. Together, these components form an interdisciplinary “wastewater toolkit” that supports methodological rigor, adaptability, and comparability across settings. By providing a structured yet flexible framework that accommodates technical variation and contextual differences, this toolkit enhances preparedness and enables the rapid establishment or optimization of wastewater surveillance systems. Gaps and inefficiencies in disease surveillance can lead to inaccurate intelligence and inadequate or inappropriate public health responses, a systematic wastewater surveillance framework is essential to generate reliable indicators of viral transmission and inform timely, evidence-based decision-making for known and emerging pathogens.

This comment prompts scholars to include eutrophication more often to water quality assessments as it is globally one of the major water-related environmental problems but remains underrepresented in contemporary assessments, water policies and international targets such as the United Nations Sustainable Development Goals (SDGs). What we scholars can do is to mainstream eutrophication in our global water assessments, and that way ram it to a higher position in political agendas. The recent advances in global nutrient models and datasets, as well as Earth observation approaches, allow novel horizons in this regard. Now is the time to scrutinize these novel opportunities. Our take to this quest here is to develop a model protocol that produces gridded eutrophication maps from total nitrogen and total phosphorus data. We also developed analogous methods for biochemical oxygen demand and total dissolved solids.

This Comment critiques current urban sanitation financing discourse and proposes sustainable cost recovery principles as a framework for more constructive conversations. The way we talk about financing matters, and a better conversation can lead to better outcomes. We contend that framing discussions around sustainable cost recovery principles can foster fairer, more sustainable financing arrangements that acknowledge sanitation as a critical public good while ensuring service provider viability and user affordability.

Unsafe water reuse in the informal irrigation sector dominates in the Global South and requires more attention to protect food safety and public health. Promoting formal wastewater use in conjunction with (usually constrained) investment in treatment capacities is not sufficient in LMIC. New approaches and indicators are needed across the formal and informal reuse sectors to increase food safety and monitor progress on safe reuse. Current reuse guidelines need to be updated with greater attention to policy, regulations, investments, and behavior change for a higher implementation potential.

Current wastewater management practices underutilize wastewater as a valuable source of water, energy, and essential plant nutrients. A new paradigm shift is needed, one that integrates the water-energy-food nexus into wastewater management. Decentralized wastewater management has the power to redefine not only the urban water cycle but also reshape society towards a more economic and environmentally sustainable future.