A Scoping Review on the Ethics of Wastewater Surveillance for COVID-19

Introduction

Wastewater surveillance (WWS) monitors sewage for indicators of population health.^1–3 Sewage may be sampled at the level of individual buildings, institutions, or communities and brought to a laboratory to test for viruses, bacteria, or chemicals that reflect chronic health conditions or health behaviors.⁴ WWS can be a cost-effective tool for informing public health action and can supplement clinical or population health data.^5,6

WWS has been used for public health applications for decades, for example to monitor polio and opioid use at a population level.⁷ WWS expanded globally during the COVID-19 pandemic to applications including institutional (e.g., universities) and community (wastewater treatment plant) testing.^8,9 Post-pandemic, efforts are underway across the world to expand the geographic reach of WWS and broader targets of testing (e.g. emerging diseases). As the application of this public health tool grows, it is important to consider the ethical implications of new use cases.

There are ethical questions about the privacy and data-use issues inherent in monitoring wastewater, particularly when applied to small and potentially identifiable groups of people. Because WWS expanded rapidly under pandemic conditions, consideration of the ethical questions it raises, effective ways of sharing results, and use of the resulting data lagged development of the technology itself.^10–12 Examining the evolution of ethical concerns as the COVID-19 pandemic progressed can shed light on how changes in public understanding, data use, governance, and risk/benefit tradeoffs may affect judgements about appropriateness of WWS to monitor other targets. As the scope and scale of monitoring wastewater for public health purposes expands, ongoing consideration of ethical practices is essential to guide appropriate use of and maintain support for this promising public health tool.^13,14

The objectives of this scoping review were to assess the existing literature on the ethics of monitoring wastewater for COVID-19 and to identify gaps in understanding about ethical conduct in the context of this expanding practice. Our goal was to inform public health agencies, researchers, and funding agencies on the emerging principles for ethical practice of WWS and on future research needs. Lessons learned from the consideration of ethics in the context of COVID-19 can inform governments, researchers, and public health professionals as they grapple with how best to sustain and develop WWS systems for new monitoring targets (e.g., pharmaceuticals, illegal drugs, infectious diseases, and indicators of population health) in the future.

Methods

We used the Johanna Briggs Institute updated methodological guidance for the conduct of scoping reviews to guide our review process.^15,16 A scoping review was appropriate to the relatively early stage of research on this topic.^15,17 We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines for Scoping Reviews for the review and analysis, and registered the scoping review protocol with Open Science Framework.¹⁶ Each step of the methodology was reviewed by both authors and a university librarian (see Acknowledgement); the final list of publications, coding themes, and draft findings were also reviewed by three additional subject matter experts.

Search strategy

An initial limited search of PubMed was undertaken to identify English-language publications on the topic. The text words contained in the titles and abstracts of relevant publications and the index terms used to describe the publications were used to develop a full search strategy. This search strategy was reviewed by a team including wastewater surveillance, public health, ethics, communication and legal experts (see Acknowledgements) and revised. The final search included components related to four concepts: 1) wastewater, 2) surveillance, 3) ethics, and 4) COVID-19. Particular attention was given to including varied terms for wastewater (e.g., blackwater, sewage, sanitation, effluent, etc.) used in different countries and contexts. Works published between January 2020 and December 2023 were included. Electronic search terms are displayed on SDC Table 1 and PRISMA chart is provided in SDC Table 2.

The authors created the search strategies in collaboration with a university librarian. Two databases were utilized: Scopus and PubMed; Google Scholar was used for manual additions. Searches were conducted in January 2024. Duplicates were removed using EndNote 21.¹⁸ We included studies published in journals, government reports and books. Because of the diversity of venues in the dataset, for simplicity we refer to the identified works as “publications.” Initial searches in Scopus and PubMed yielded 71 publications. Five additional publications were manually added to the initial list after consultation with subject area experts, for a final list of 76 publications.

Study selection

Both authors independently analyzed abstracts and titles to exclude any papers that did not substantively focus on the ethics of WWS for COVID-19. For example, we excluded publications that focused primarily on endpoints other than COVID-19 or limited their discussion of ethics to the legality of sample collection and did not discuss ethics of data use or public health action in the context of the pandemic. Papers that mentioned ethics as potential concern but did not substantively discuss ethical issues were excluded. Any discrepancies were resolved by discussion between the two authors. This process narrowed the initial list of 76 publications to 33, and full text analysis further narrowed this to 31 publications (Table 1). We collected PDFs for included publications, and both authors independently evaluated full-text records to confirm they met the inclusion criteria for the review.

Table 1:

Reviewed publications on ethics of wastewater surveillance for COVID-19

Title	Authors	Date	Source / Journal
The Chelsea Project: Turning Research and Wastewater Surveillance on COVID-19 Into Health Equity Action, Massachusetts, 2020–2021	C. Alonso, B. Keppard, S. Bates et al.	2023	American Journal of Public Health
Structured Ethical Review for Wastewater-Based Testing in Support of Public Health	D. A. Bowes, A. Darling, E. M. Driver et al.	2023	Environmental Science and Technology
Canadian Coalition on Wastewater-related COVID-19 Research	Canadian Water Network	2020	Canadian Water Network (report)
Building health system resilience and pandemic preparedness using wastewater-based epidemiology from SARS-CoV-2 monitoring in Bengaluru, India	A. Chaudhuri, A. Pangaria, C. Sodhi et al.	2023	Frontiers in Public Health
Preventing Scientific and Ethical Misuse of Wastewater Surveillance Data	M. M. Coffman, J. S. Guest, M. K. Wolfe et al.	2021	Environmental Science and Technology
Maintaining a social license to operate for wastewater-based monitoring: The case of managing infectious disease and the COVID-19 pandemic	B. Cooper, E. Donner, L. Crase, et al.	2022	Journal of Environmental Management
Opinions of former jail residents about self-collection of SARS-CoV-2 specimens, paired with wastewater surveillance: A qualitative study rapidly examining acceptability of COVID-19 mitigation measures	M. del Mar González-Montalvo, P. F. Dickson, L. B. Saber et al.	2023	PLoS ONE
Wastewater research and surveillance: an ethical exploration	Doorn N.	2022	Environmental Science: Water Research and Technology
Expansion and diversification of wastewater-based epidemiology strategies in pandemic conditions to serve immediate public health goals	E. M. Driver, D. A. Bowes and R. U. Halden	2023	Wastewater-Based Epidemiology for the Assessment of Human Exposure to Environmental Pollutants (book)
Legal and ethical implications of wastewater monitoring of SARS-CoV-2 for COVID-19 surveillance	L. Gable, N. Ram and J. L. Ram	2020	Journal of Law and the Biosciences
Public Awareness of and Support for the Use of Wastewater for SARS-CoV-2 Monitoring: A Community Survey in Louisville, Kentucky	R. H. Holm, J. M. Brick, A. R. Amraotkar et al.	2022	ACS Environmental Science and Technology Water
Beyond COVID-19: Designing Inclusive Public Health Surveillance by Including Wastewater Monitoring	R. H. Holm, N. O. Jelks, R. Schneider et al.	2023a	Health Equity
Using wastewater to overcome health disparities among rural residents	R. H. Holm, G. Pocock, M. A. Severson et al.	2023b	Geoforum
Public health benefits and ethical aspects in the collection and open sharing of wastewater-based epidemic data on covid-19	R. Honda, M. Murakami, A. Hata et al.	2021	Data Science Journal
Ethics Guidance for Environmental Scientists Engaged in Surveillance of Wastewater for SARS-CoV-2	S. E. Hrudey, D. S. Silva, J. Shelley et al.	2021	Environmental Science and Technology
Expansion of wastewater-based disease surveillance to improve health equity in California’s Central Valley: sequential shifts in case-to-wastewater and hospitalization-to-wastewater ratios	K. F. Kadonsky, C. C. Naughton, M. Susa et al.	2023	Frontiers in Public Health
Developing a flexible national wastewater surveillance system for COVID-19 and beyond	A. Keshaviah, X. C. Hu and M. Henry	2021	Environmental Health Perspectives
Nationwide public perceptions regarding the acceptance of using wastewater for community health monitoring in the United States	A. S. LaJoie, R. H. Holm, L. B. Anderson et al.	2022	PLoS ONE
Wastewater surveillance in smaller college communities may aid future public health initiatives	L. Lee, L. Valmond, J. Thomas et al.	2022	PLoS ONE
To sample or not to sample: A governance-focused decision tree for wastewater service providers considering participation in wastewater-based epidemiology (WBE) in support of public health programs	R. Maal-Bared, K. Brisolara, M. Knight et al.	2023	Science of the Total Environment
COVID-19 surveillance in wastewater: Communications and equity	S. Manning and M. Walton	2021	Institute of Environmental Science and Research
SARS-CoV-2 wastewater surveillance for public health action	J. S. McClary-Gutierrez, M. C. Mattioli, and P. Marcenac	2021	Emerging Infectious Diseases
The need of an environmental justice approach for wastewater-based epidemiology for rural and disadvantaged communities: A review in California	C. Y. Medina, K. F. Kadonsky, F. A. Roman et al.	2022	Environmental Science and Technology
Letter to the Editor: Wastewater-Based Epidemiology Can Overcome Representativeness and Stigma Issues Related to COVID-19	M. Murakami, A. Hata, R. Honda et al.	2021	Environmental Science and Technology
Wastewater-based disease surveillance for public health action	National Academies of Science, Engineering and Medicine	2023	NASEM (report)
Show us the data: global COVID-19 wastewater monitoring efforts, equity, and gaps	C. C. Naughton, F. A. Roman, A. G. F. Alvarado et al.	2023	FEMS Microbes
The Future of Wastewater Monitoring for the Public Health	N. Ram, L. Gable and J. L. Ram	2022	University of Richmond Law Review
Coping with COVID in corrections: a qualitative study among the recently incarcerated on infection control and the acceptability of wastewater-based surveillance	L. R. Riback, P. Dickson, and K. Ralph	2023	Health and Justice
Research needs for optimising wastewater-based epidemiology monitoring for public health protection	K. Robins, A. F. C. Leonard, K. Farkas et al.	2022	J. Water Health
The Datafication of Wastewater:: Legal, Ethical and Civic Considerations	T. Scassa, P. Robinson and R. Mosoff	2022	Technology and Regulation
Establishing New Zealand’s national pathogen surveillance system using wastewater-based epidemiology	S. Trowsdale, B. Gilpin, K. Sila-Nowicka et al.	2022	Journal of Hydrology New Zealand

Data extraction and analysis

Data extracted included details about the publications (title, first author, publication year, journal name or type of work (book, report, etc.)), the region(s) the manuscript applied to, disciplinary focus of the publication venue (e.g., science, public health, social science, other), and publication type (research, government report, commentary/perspective, or other). We also characterized the primary approach of each publication according to its main aim: identifying ethical issues raised by a case study (“case study”), empirical exploration of people’s ethical concerns (e.g., through surveys, interviews, or focus groups) (“empirical”), identifying the need for ethical guidelines (“need for guidelines”), or proposing ethical guidelines (“proposes guidelines”) (SDC Table 3). Brief notes about the objective, context, and main findings of the publication were also recorded. Data extraction was performed independently by the co-authors and any differences reconciled through discussion. Data were recorded in an Excel spreadsheet to facilitate characterization of the publications.

Thematic coding and analysis

Thematic analysis was performed to identify themes related to the ethics of wastewater monitoring of wastewater for COVID-19. The authors identified emergent themes from the publications and consultation with experts in the fields of WWS and bioethics. These discovered themes were compiled by the authors and reviewed by the a team of experts (see Acknowledgements) to develop a final coding guide (Table 1).

Each publication was coded independently by the two authors. Differences were resolved through discussion. Results of the final coding were recorded in an Excel spreadsheet to facilitate calculation of frequency and analysis of patterns of association between publication characteristics and themes (SDC Table 4).

Results

This section briefly summarizes the characteristics of the reviewed publications (region of study, main approach or aim, discipline of venue, and type of publication) and the thematic analysis.

Characterization of reviewed publications

The approaches and aims of the reviewed publications varied widely (Table 3). Over a third of the publications (12) focused on the need to develop and apply ethical guidelines (“need for guidelines”) to the practice of WWS. Most of these works were predominantly hypothetical, making conceptual arguments about the ethical issues raised by WWS, the need for development of principles to guide practice or and the potential to applying existing ethical principles to this new issue area. Six (6) publications aimed to propose ethical guidelines (“proposes guidelines”) specifically for WWS for COVID-19. Several of these emphasized both the need for guidelines and suggested principles as a framework to build on, most commonly drawing from the World Health Organization’s 2017 Guidelines for Ethical Issues in Public Health Surveillance.¹⁹ Most publications that articulated specific guidelines also noted that it is not possible to identify universal rules for this evolving practice, but rather emphasized the importance of developing sustainable systems for integrating context-specific expert and public opinions. Nearly a third (10) of the publications analysed the ethical implications and challenges encountered in specific applications of WWS for COVID-19 (“case study”). Many of these case studies also reflected on the need to develop ethical guidelines to inform future practice. Three publications empirically explored public perceptions, knowledge, and preferences about WWS through surveys, interviews, or focus groups (“empirical”). Thus, based on our analysis, the literature to date has emphasized development of conceptual guidelines, with relatively little work that empirically explores stakeholder preferences or applied experiences in real community settings where WWS has been implemented.

Table 3:

Ethical themes identified in reviewed publications by aim/approach

	Privacy	Stigma	Effective Communication	Equity	Public Trust	Community Engagement	Data Quality	TOTAL BY AIM
Need for Guidelines	9	9	7	6	3	4	1	12
Proposes Guidelines	6	6	5	0	2	2	4	6
Case Study	5	1	3	8	3	2	2	10
Empirical	2	2	1	1	1	0	0	3
TOTAL	22	18	16	15	9	8	7

We categorized each publication with respect to study area or geographic relevance (SDC Table 3). Fifteen publications did not specify a geographic region, with the implied intention of being globally relevant. This included all 12 the publications whose approach emphasized the need for guidelines. Importantly, several of these “global” publications noted that ethical principles might vary by cultural or geographic context. Of the 16 publications that specified a geographic context, 12 were grounded in a U.S. context and one focused on Canada. The three non-North American publications related to case studies in India, New Zealand, and the United Kingdom. It is important to note that authors of many of the publications were identified with institutions outside of North America. Their geographic, political, or cultural context may have informed their approach to the ethics of WWS, but their work was presented as globally relevant. The ethics of WWS are clearly of global importance, and differences are expected between across varied cultural, geographic, economic, and political contexts. However, there have been limited efforts to explicitly address these local differences in the existing literature.

We identified the disciplinary focus of the publication venues to provide insight into which scholarly fields have been most engaged in exploring the ethics of WWS (SDC Table 3). It was beyond the scope of this review to discern the disciplinary training, experience, or approach of authors, particularly since so many publications were produced by transdisciplinary teams. Nearly half of the publications (15) were in venues categorized broadly as science (e.g., engineering, water, environmental science). Six articles were in journals coded as “public health” and an additional four in other types of social science journals. The remaining six publications were published in other types of academic journals, government and non-government organization reports, and books. While scientific disciplines have clearly raised concerns about the ethics of WWS, there is a dearth of attention to this topic in publications dedicated to humanities or social science perspectives.

Seventeen of the 31 publications were described as commentary or perspective articles, including 9 of the 15 published in “science” journals. Twelve of the publications were characterized by the journal as “research” articles, half of which were in science journals, half in other venues. The remaining 2 publications were lengthy government and non-government agency reports. Thus, while original research has been conducted on the ethics of wastewater surveillance, the majority of publications we reviewed were short commentaries.

Thematic Analysis

Each publication was coded to identify which of the seven themes they addressed. Most articles discussed multiple themes. Findings related to each theme (Table 1) are briefly discussed below in order of the number of publications that explicitly addressed them (Table 2 and Table 3 (see “Total”)). Results of the thematic coding of the publications are provided in SDC Table 4.

Table 2:

Definitions of themes for coding ethics of wastewater surveillance

Theme	Definition
Privacy	Addresses concerns that monitoring efforts will infringe upon individuals’ privacy rights. Includes discussion of the scale of monitoring (e.g., community-wide versus building level) or the identifiability of results.
Stigma	Raises concern that certain communities, particularly historically under-resourced communities, would be unfairly burdened by public health-related restrictions triggered by community-wide monitoring results.
Effective Communication	Emphasizes communicating wastewater surveillance findings in a timely, clear and effective way to the public and data users.
Equity	Frames wastewater surveillance as a public health resource that should be widely available to all communities, particularly to those that are rural, have low clinical testing rates, and have limited access to health services.
Public Trust	Claims or implies that public trust in wastewater surveillance efforts is a prerequisite for funding and political support needed to sustain them over time. In this framing, consideration of ethics aims to bolster public trust.
Community Engagement	Argues that community representatives and stakeholders should be consulted about the implementation, design and use of the data.
Data Quality	Emphasizes that the data provided by wastewater surveillance efforts must be high quality and reliable, and that uncertainty should be communicated clearly.

Privacy (22):

Privacy was a dominant issue in the literature on the ethics of WWS we reviewed. The risk of identifying individuals associated with data derived from community-scale WWS for COVID-19 is low. However, privacy could be an issue for small sewershed or building-level surveillance. As technology develops and as other monitoring endpoints are considered, the risk of individual identification may increase. Most of the discussions of privacy in the reviewed publications highlighted that WWS protects individual privacy compared to clinical testing, but that very localized monitoring (e.g., individual residences or institutions) could pose privacy risks. Privacy was frequently referenced as an ethical consideration in determining the appropriate scale (e.g., number of individuals within the monitored sewershed) of WWS.

Stigma (18):

The second most frequently cited ethical concern was that uninfected people could be unfairly burdened by public perceptions or legal restrictions based on community-wide monitoring efforts. Many authors who noted concerns about stigma focused on outcomes for communities with limited or no clinical testing. In other words, the context of this concern was that: 1) WWS could provide evidence of infection where prior data did not exist and 2) this data could result in restrictions such as masking, social distancing, or shutdowns that burden all residents, including those who are not infected. A related concern was that publication of WWS data might “stigmatize” a certain area or population group in the public eye as having high rates of infection, leading to loss of business, job discrimination, etc. Stigma concerns were most frequently raised in the context of monitoring populations that have been historically under-resourced and disadvantaged.

Effective Communication (16):

Many publications characterized clear and timely communication of WWS data to the public as an ethical obligation. Several referenced the 2017 WHO guidelines that include “effective communication” as a key principle. Many noted that “effective communication” was complicated by the uncertainties inherent interpreting the meaning of WWS results, particularly early in the pandemic, complicated this task.^7,20 Effective communication to the public and stakeholders helps maximize benefits of WWS because it enables them to make well-informed decisions at the personal, institutional, or policy level. Several authors also noted that effective communication and transparency over time was also essential to building public trust. A subtheme in several publications was that researchers and technical experts who provide WWS data may not have experience and skills in appropriately communicating public health information to diverse stakeholders.^11,20,21

Equity (15):

Most of the publications in which the “equity” theme was identified revolved around arguments that WWS is a benefit that should be available fairly to all communities. In other words, WWS is a public good because of the potential to identify areas with increasing infection rates and quickly provide resources to mitigate these trends. As with the “stigma” theme, equity was frequently raised in the context of lower-resourced communities, including rural populations, unsewered areas, and communities with low clinical testing rates. Several publications extended this theme to argue that WWS resources should be targeted at areas with limited clinical testing, preventive services, and health care resources.

Public Trust (9):

A primary rationale these publications presented for developing ethically acceptable WWS was the necessity of public trust for sustaining WWS. In other words, because WWS is not required by regulation in most jurisdictions, funding and political support to sustain the practice depends on public trust. Many of these publications stated or implied that public trust is essential to sustain the long-term beneficial role of WWS in society, and that public perception that WWS is ethical is key to public support. For example, Cooper et al²¹ framed public trust as essential to maintaining a “social license to operate” WWS.

Community Engagement (8):

Many publications explicitly noted the importance of community engagement in identifying ethical considerations and informing the design, implementation, and use of data from WWS. They emphasized that engagement may help build understanding of and public trust in WWS. Several authors noted that community values around themes like privacy and stigma are likely to vary from place to place, making local engagement essential. As well, they noted that preferences may shift over time, necessitating ongoing interaction. In many cases, the themes of effective communication and public trust were connected to arguments in support of community engagement.

Data Quality (7):

Assuring high data quality is important to maximize the usefulness of WWS to inform decision making. Several articles explicitly describe providing quality data – and clearly communicating uncertainties – as an ethical issue in the context of WHO guidelines (Guideline 4: “Countries have an obligation to ensure that the data collected are of sufficient quality, including being timely, reliable, and valid, to achieve public health goals”).¹⁹ However, what constitutes “sufficient quality” in the case of WWS is complicated. As the WHO guidelines point out, adequacy of data depends on the level of intervention (individual or community), the nature of the measured indicator (infectious, noncommunicable or environmental, severity, etc.), and the importance of speed/early warning versus reliability. Therefore, understanding and communicating the quality of WWS data in the context of their intended use is a fundamental ethical consideration.

An overarching concept integrating these themes was that public health interventions involve balancing potential risks and benefits. In addition to its potential benefits (e.g. informing timely, cost-effective, equitable public health action), WWS poses a potential burden to society (e.g. costs of sampling, potential threats to privacy, triggering burdensome restrictions). Although many of the empirical and case study-based publications did not directly reference this dynamic, this tension helps to explain the diversity in approaches and arguments within this literature. For example, those who frame WWS as a public health benefit that will help allocate limited resources to better promote health equity tended to emphasize an ethical mandate to make WWS available to lower-resourced communities (equity). Those that focused on the potential burdens that could be imposed as a result of WWS data tended to emphasize privacy and stigma concerns. In other words, intended and actual data use is a key determinant of ethical practice of WWS.

Thus, ethical arguments require making assumptions about or providing frameworks for consideration of how the WWS data is used. Many of the publications that explicitly recognized trade-offs between benefits and risks of WWS data use presented a dynamic view that “ethical” WWS depends on many contextual factors and is likely to change over time. These authors emphasized the need for sustained, locally engaged systems for public input to and governance of WWS practice.

However, several publications noted that a challenge to integrating community input is the public’s general lack of knowledge about WWS systems.^7,22,23 This gap in fundamental understanding makes it difficult to meaningfully assess and address public preferences with respect to WWS. Thus, ethical practice of WWS may require significant efforts to educate, elicit preferences from, and engage diverse stakeholders.

Discussion

This scoping review contributes to understanding of the ethics of WWS by characterizing the existing scholarship and identifying gaps. Although several of the publications provided well-developed principles, frameworks, and ethical considerations, none reported on cases in which these approaches have been systematically implemented.

One goal of this review was to identify approaches to WWS ethics that practitioners might apply to their work. Of the six publications that explicitly offered guidance for ethical practices, four^7,20,24,25 build on the 2017 WHO Guidelines on Ethical Issues in Public Health Surveillance.¹⁹ While these publications offer a framework for applying existing public health guidelines to the context of WWS, and COVID-19 in particular, they emphasize that these principles must be revisited for each new monitoring target, community, and changing public health contexts over time. These principles are also consistent with the American Public Health Association (APHA) Code of Public Health Ethics.²⁶ Although the APHA Code of Public Health Ethics is not specific to surveillance, these guidelines reinforce the idea that ethical surveillance practices are entwined with contextual factors including data quality, communication, and use.

A second goal of this review was to detail gaps in knowledge and needs for additional research. Across the publications reviewed in this study, there was very little empirical work: the ethical concerns presented were largely hypothetical, rather than voiced by affected parties (e.g., general public, wastewater treatment plant operators, public health professionals). Indeed, the case studies and surveys that have been conducted did not indicate widespread concern about most of the ethical considerations raised by the reviewed publications, with the exception of privacy concerns associated with small-scale (i.e., residential or institutional) monitoring.^22,23 This suggests that additional research is needed on public understanding, perceptions, and concerns in a variety of contexts in which WWS has been implemented.

Overall, these publications emphasized that ethical WWS depends on context. For example, although we focused on WWS for COVID-19, many of the publications explored ethical considerations across additional target measurements (e.g., illicit drugs, prescription drugs, other infectious diseases, etc.). Another gap is exploring how trade-offs between risk and benefits vary based on cultural or national contexts. Regardless of location, this suggests that ethical WWS requires a sustained system for eliciting diverse perspectives and evolving guidelines to reflect changing values, benefits, and burdens of data use. These themes were strongly affirmed in the Association for State and Territorial Health Official’s 2025 framework for consideration of ethics in decision-making about WWS.¹⁴

Limitations

This scoping review had a number of limitations. The search strategy may have missed relevant publications. For example, although we reviewed the search terms with experts from multiple countries, different terms may be used in different countries. As well, there may be publications that discussed ethical issues in the text – for example, in discussion of results – but did not use an ethics-related term in the title or abstract. The WWS enterprise is inherently multidisciplinary, and relevant publications may not be indexed in the primary search engines we used. Our manual search attempted to account for this diversity of venues, but may not have been complete. Because WWS is an emerging practice of public health, there may be important additional contributions in the form of gray literature, academic theses, and practice reports we were unable to identify. Our review of global perspectives on the ethics of WWS was likely limited by our exclusion of non-English language publications. Particularly given the reviewed publications’ emphasis on the cultural, political, and social diversity of ethical considerations, future efforts are needed to elicit non-North American perspectives on and experiences with WWS.

Conclusions

1. The most commonly identified ethical concern about WWS in the reviewed publications was privacy, followed by stigma, effective communication, and equity.

2. Conducting WWS within community-informed ethical guiderails is an essential foundation for sustained public support of this promising public health practice.

3. The public’s limited understanding of WWS is a barrier to eliciting community input on ethical considerations.

4. Risks and benefits of WWS differ based on context, including geographic, political, and cultural factors.

5. Significant gaps in the existing literature include limited empirical studies and research on how ethical considerations may vary across the globe.

Implications for Policy & Practice:

Wastewater surveillance (WWS) is a promising, cost-effective tool for informing public health decisions. Implementing ethical principles in WWS is important to building public trust in and sustained support for this practice. As WWS expands geographically and is applied to varied public health indicators, systems should be developed to elicit broad stakeholder input in the collection and use of these data.