Wastewater Monitoring: Improving Public Awareness and Understanding in the United States, May 2024

Abstract

Objectives:

Although wastewater monitoring for virus detection has increased in communities worldwide, public awareness, understanding, questions, and concerns about wastewater monitoring are largely unknown. We assessed awareness, knowledge, and support for wastewater monitoring for detection of viruses and bacteria among US residents and elicited questions and concerns from residents about its use.

Methods:

We conducted a survey among a racially and ethnically diverse sample of residents in Colorado, Maryland, Missouri, Nebraska, and Texas to assess awareness, knowledge, and support of wastewater monitoring. We also asked an open-ended question to elicit further questions and concerns from survey participants about wastewater monitoring. Two independent reviewers coded the responses to the open-ended question.

Results:

Among 516 survey participants (52% White, 31% Black, 27% Hispanic ethnicity), 289 (56%) were aware that local public health departments and federal health agencies tested sewer water yet 334 (65%) knew “little or nothing” about wastewater monitoring. After participants were exposed to a brief description of the wastewater monitoring process, 80% “supported” or “strongly supported” wastewater monitoring to detect viruses and bacteria. When we analyzed responses to the open-ended question on wastewater monitoring, 3 broad categories and 9 subcategories of questions and concerns about wastewater monitoring emerged: (1) how wastewater monitoring works (mechanics, accuracy, cost, safety), (2) what is done with the findings generated by wastewater monitoring (public accessibility, government trust, public health response), and (3) what protections were in place against misuse of findings (privacy, fairness).

Conclusions:

Proactive public education is needed to increase understanding, build support, and prevent disinformation about wastewater monitoring. Local systems are needed to share findings rapidly, clearly, and simply.

Wastewater monitoring is increasingly part of surveillance efforts in public health to detect and respond to infectious disease outbreaks.^1-4 The identification of traces of viruses and other infectious agents in a community’s wastewater is an important early indicator that certain infections are increasing or decreasing. Sharing of wastewater monitoring findings with the public is not yet the norm ⁵ but has considerable potential value. ⁶ Evidence has suggested that individuals regulate their protective behaviors as community-level infection rates rise and fall. ⁷ Greater public awareness of wastewater monitoring findings could help reduce the spread of infectious diseases.

For the public to act on wastewater monitoring data, residents need to understand how wastewater monitoring works, have easy access to simple data interpretations with unmistakable meaning, and trust that both data sources and monitoring will be applied ethically and fairly. ⁸ This latter point is especially important given well-documented mistrust of government health efforts among certain racial, ethnic, and rural groups.^{9 -11}

In the only national public opinion study of wastewater monitoring published to date, researchers assessed support for the use of sewer monitoring to track various health indicators; researchers found that the strongest support was for monitoring of diseases (91% supported) and environmental toxins (92% supported). ⁸ However, the study excluded rural residents, and its internet-based sample of US residents was 84% White. In the only local public awareness survey on wastewater monitoring to our knowledge, researchers again found broad support for monitoring wastewater for diseases, ¹² with support being stronger among people with more knowledge (vs less knowledge) about the monitoring process (eg, that viruses could be detected in wastewater and that the amount of virus detected reflects community infection rates). The proportion of respondents from racial minority groups in the local sample was small.

Our study builds on evidence from these surveys by assessing public knowledge about and support for wastewater monitoring and extends findings from previous surveys by eliciting and coding questions and concerns from the public on wastewater monitoring. Because our 5-state sample was racially, ethnically, and geographically diverse, we can examine how public awareness, knowledge, questions, and concerns vary across population groups. We interpreted these findings in the context of building public knowledge and trust in public health data, methods, and organizations.

Methods

Sample

We sent a mobile telephone survey to 633 adults residing or working in Colorado, Maryland, Missouri, Nebraska, and Texas who were participating in iHeard community panels. iHeard is a weekly health knowledge monitoring and response system with local sites in various states. ¹³ For inclusion in community panels, iHeard researchers recruited people (aged ≥18 y) who lived or worked in local sites through community partner organizations, with an intention to recruit people from demographic groups who were experiencing a disproportionate health burden locally. Participants in the Missouri panel began responding to weekly surveys in August 2021; other panels launched in September 2023 (Nebraska), October 2023 (Colorado), December 2023 (Maryland), and March 2024 (Texas). Nearly all panel members lived in communities with active wastewater monitoring systems.

The institutional review boards (IRBs) of the University of Nebraska Omaha (IRB protocol 0493-23-EX), Washington University in St. Louis (IRB protocol 202107196), University of Colorado (IRB protocol 21-3647), Johns Hopkins University (IRB protocol 00393597), and University of North Texas (IRB protocol 2109547-1) approved the study. Each site obtained written informed consent from panel members.

Data Collection

Every Saturday, we sent panel members a link to a Qualtrics survey by text message or email, allowing participants 48 hours to respond. We conducted the survey on wastewater monitoring from May 25 to 27, 2024. We gave panel members $5 or $10 for completing each survey.

Measures

In the wastewater monitoring survey, we assessed awareness, understanding, and support of wastewater monitoring among panel members. We also included an open-ended question on wastewater monitoring to elicit further questions and concerns. We adapted survey items on awareness, understanding, and support from LaJoie et al. ⁸

We assessed awareness by asking, “Local [public] health departments and federal agencies like CDC [Centers for Disease Control and Prevention], FDA [US Food and Drug Administration], and EPA [US Environmental Protection Agency] monitor community health in many ways. Which of these are you aware of?” We presented the following yes/no choices in randomized order: monitoring air pollution, testing drinking water, testing sewer water, inspecting restaurants, and inspecting buildings.

We assessed understanding by asking, “How much do you know about testing sewer water, sometimes called ‘wastewater monitoring?’” Responses were a lot, some, and little or nothing.

To assess support, we provided the following brief description of wastewater monitoring, which was followed by a question: “When people have certain infections, they shed parts of the virus or bacteria when they use the toilet, take a bath or shower, or just wash their hands. These particles travel through plumbing pipes and into the sewer system. Samples of sewer water can then be tested to see how much of a virus or bacteria is in the community. This is called ‘wastewater monitoring.’ Do you support or oppose using wastewater monitoring to detect viruses or bacteria in a community?” Responses were strongly support, support, neither support nor oppose, oppose, and strongly oppose.

To elicit further questions and concerns, we asked, “What questions or concerns do you have about wastewater monitoring?”

We obtained data on age, race and ethnicity, sex, and urban or rural residence of panel members from data obtained at enrollment when individuals joined the iHeard panel. ¹³ We grouped age as 18 to 29, 30 to 39, 40 to 49, 50 to 59, and ≥60 years.

Analysis

We conducted quantitative analyses with R version 4.3.1 (R Foundation for Statistical Computing). We used the Pearson χ² test to examine bivariate associations between awareness, understanding, and support of wastewater monitoring and characteristics of survey respondents, with P < .05 considered significant. We handled missing data with listwise deletion.

We coded responses to the open-ended question by using reflexive thematic analysis. ¹⁴ This 4-step process began with 1 author (A.O.) identifying initial themes, another author (A.K.M.) modifying the themes, and then 2 authors (A.O., A.K.M.) independently coding all responses into the theme areas. Two authors (M.W.K., R.G.) then resolved coding discrepancies and grouped the themes into 3 categories and 9 subcategories: (1) how wastewater monitoring works (mechanics, accuracy, cost, safety), (2) what is done with wastewater monitoring findings (public accessibility, government trust, public health response), and (3) protections against misuse of wastewater monitoring data (privacy, fairness). We calculated the Cohen κ to determine the interrater reliability, ¹⁵ with values of 0.61 to 0.80 signifying substantial intercoder agreement and values of 0.81 to 1.00 signifying almost perfect intercoder agreement. ¹⁶ We conducted bivariate analyses to examine whether expressing questions or concerns in each of the 3 categories or 9 subcategories was associated with characteristics of survey respondents.

Six of 8 respondents who completed the survey in Spanish responded to the open-ended question. We translated these responses with Chat GPT Beta (OpenAI) and a bilingual research team member and coded them.

Results

Survey Respondents

Of 633 panel members, 516 (82%) completed the survey. Response rates did not vary significantly by state. Among 516 respondents, 268 (52%) were White and 158 (31%) were Black; 140 respondents (27%) reported Hispanic ethnicity. The mean age of respondents was 42.4 years; 324 respondents (63%) were women, and 43 (8%) were rural residents (Table 1).

Table 1.

Awareness and knowledge of and support for wastewater monitoring by demographic characteristics of survey respondents from 5 states, 2024 ^a

Characteristics	No. of respondents b	No. (%) of respondents
		Aware of wastewater monitoring (n = 516)	Know little or nothing about wastewater monitoring (n = 514)	Support or strongly support wastewater monitoring (n = 516)
All respondents	516	289 (56)	334 (65)	415 (80)
Sex
Female	324	168 (52) c	229 (71) c	258 (80)
Male	189	119 (63) c	104 (55) c	154 (82)
Race
Black	158	90 (57)	101 (64)	129 (82) c
White	268	150 (56)	178 (66)	221 (83) c
Other d	90	49 (54)	55 (62)	65 (72) c
Ethnicity
Hispanic	140	73 (52)	95 (68)	110 (79) c
Non-Hispanic	372	214 (57)	235 (64)	303 (82) c
Residence
Rural	43	18 (42) c	30 (70)	32 (74)
Urban	470	271 (58) c	303 (65)	381 (81)
Age group, y
18-29	112	57 (51)	72 (65)	88 (79)
30-39	143	75 (52)	93 (66)	109 (76)
40-49	109	67 (62)	75 (69)	89 (82)
50-59	79	45 (57)	52 (66)	63 (80)
≥60	71	45 (63)	41 (58)	64 (90)

^aSurvey respondents were from Colorado, Maryland, Missouri, Nebraska, and Texas and had been recruited to iHeard community panels. iHeard is a weekly health knowledge monitoring and response system with local sites in various states. ¹³

^bResponses by sex, ethnicity, residence, and age do not total to 516 because of item nonresponse and/or (for sex) nonbinary response.

^cSignificant at P < .05 using the Pearson χ² test.

^dOther included respondents who did not indicate Black or White.

Awareness, Understanding, and Support

Among 516 respondents, 289 (56%) were aware that governments tested sewer water (Table 1). This rate of awareness was lower than respondents’ awareness of monitoring drinking water (n = 394; 76%) and inspecting restaurants (n = 330; 64%) and about the same as awareness of monitoring air pollution (n = 295; 57%). Awareness of testing sewer water was significantly higher among men (119 of 189; 63%) than among women (168 of 324; 52%) (χ² = 6.12; P = .047) and higher among urban residents (271 of 470; 58%) than among rural residents (18 of 43; 42%) (χ² = 4.00; P = .046).

Among 516 respondents, 334 (65%) reported knowing little or nothing about wastewater monitoring, 153 (30%) reported knowing some, and 27 (5%) reported knowing a lot. A significantly smaller percentage of men (104 of 187; 56%) than women (229 of 324; 71%) reported knowing little or nothing about wastewater monitoring (χ² = 12.3; P = .002).

Most respondents expressed support (224 of 516; 43%) or strong support (191 of 516; 37%) for using wastewater monitoring to detect viruses or bacteria in a community; 18 of 516 (3%) were opposed or strongly opposed to wastewater monitoring, and 83 of 516 (16%) neither supported nor opposed wastewater monitoring. Among the 27 participants who reported knowing a lot about wastewater monitoring, 100% expressed support or strong support for it; support or strong support was also expressed by 140 of 153 participants (92%) who had some knowledge and 248 of 334 participants (74%) who reported knowing little or nothing about wastewater monitoring. Respondents who were Black (vs. White) were more likely to oppose or strongly oppose wastewater monitoring (10 of 158 [6%] vs 4 of 268 [2%]) but were significantly more likely to support or strongly support wastewater monitoring than respondents who indicated other race (ie, not Black or White) (129 of 158 [82%] vs 65 of 90 [72%]) (χ² = 12.43; P = .01).

Questions and Concerns About Wastewater Monitoring

Among 516 respondents, 291 (56%) responded to the open-ended question. Providing any response to the open-ended question (yes/no) was not associated with a person’s level of understanding of wastewater monitoring. Nonsubstantive responses (eg, “none,” “no questions”) were not coded (n = 131 respondents). Respondents aged ≥60 years were significantly more likely than those aged <60 years (31 of 71 [44%] vs 128 of 443 [29%]) to provide substantive responses (χ² = 6.25; P = .01); women were also significantly more likely than men (117 of 324 [36%] vs 43 of 189 [23%]) to provide substantive responses (χ² = 9.23; P = .003).

Among the 160 coded responses, 86 questions and concerns (54%) were about how wastewater monitoring works, 38 (24%) were about what is done with the findings from wastewater monitoring, and 17 (11%) were about protections against misusing wastewater monitoring data (Table 2). Some responses addressed multiple categories and could be included in both. We coded the remaining 33 responses (21%) as “other” because they were not about wastewater monitoring (eg, “there are rumors that some bottled water is actually purified sewer water”) or did not express a question or concern (eg, “this is something that should be done”). The Cohen κ ranged from 0.67 to 0.68.

Table 2.

Questions and concerns of survey respondents from 5 states in response to an open-ended question about wastewater monitoring, 2024 ^a

Category and subcategory	No./total (%) of subcategory responses	Representative question or concern
How wastewater monitoring works (86 responses [54%]; Cohen κ = 0.67)
Mechanics of wastewater monitoring	37/86 (43)	How are the tests conducted? What equipment is used? How quickly does the test work?
Accuracy of findings	20/86 (23)	Is it confirmed that this actually works? Is it effective for monitoring both bacteria and viruses? Is it effective at pinpointing exact communities and specific locations or just larger areas?
Community safety	19/86 (22)	How clean is our water? Will it impact the water we drink? Is it properly being disposed of?
Cost-related questions and concerns	13/86 (15)	How much is it going to cost? Is this something that would become privatized? Would this be used as an excuse to increase the cost of [utilities]?
What is done with data generated by wastewater monitoring (38 responses [24%]; Cohen κ = 0.68)
Public accessibility	24/38 (63)	Are results made public? How are they relaying the information to the community? How can the average person learn more about this?
Public health/government response	16/38 (42)	What is done after a specific pathogen is identified? How do the results influence medical practice? Will other forms of tracking/testing be used less?
Protections against misuse of wastewater monitoring data (17 responses [11%]; Cohen κ = 0.67)
Fairness	10/17 (59)	Rural communities like farms have private septic systems. Questions on accuracy regarding communities/areas that have less access to toilets/sinks and showers. Maybe testing needs to be stepped up in certain areas that seem to be problematic for hard-to-treat bacteria.
Privacy	8/17 (47)	Invasion of privacy. Concerns about how granular the collected data could get, especially if individual source buildings are identified. Concerns that both privacy is protected and people who need medical assistance get notified.

^aSurvey respondents were from Colorado, Maryland, Missouri, Nebraska, and Texas and had been recruited to iHeard community panels; 291 of 516 survey respondents answered the open-ended question, of which 160 responses were coded into categories and then into subcategories by the authors. iHeard is a weekly health knowledge monitoring and response system with local sites in various states. ¹³

How Wastewater Monitoring Works

Among the 86 elicited questions or concerns about how wastewater monitoring works, 37 (43%) were related to its mechanics, such as timing (eg, “How frequently is it done?”), procedures (eg, “How are the tests conducted?”, “How quickly does the test work?”), and scope (eg, “Are wells being tested?”); 20 (23%) addressed accuracy (eg, “How accurate is it?”, “Does it actually work?”); and 19 (22%) were about threshold levels for community safety (eg, “What [are] considered unsafe levels?”).

Thirteen of 86 questions (15%) were related to cost, ranging from general (eg, “How much it’s going to cost”) to personal (eg, “Will this affect the amount of the water bill?”, “How much does this cost the taxpayer?”) or addressing relative value (eg, “Are the benefits greater than the costs?”, “How much does this cost in comparison to other measures?”) or concerns about government sustainability (eg, “Not enough funding to properly manage issues”). Respondents aged <60 years (77 of 128; 60%) were significantly more likely than respondents aged ≥60 years (9 of 31; 29%) to ask questions about how wastewater monitoring works (χ² = 9.74; P = .002).

Use of Findings From Wastewater Monitoring

Most questions or concerns from respondents about how wastewater monitoring findings are used focused on sharing findings with the public. Three themes emerged: (1) results should be public (eg, “Make sure testing information is required to be shared publicly,” “I would like for information to be public so that we can as a community see what exactly is happening,” “When disease or problematic results are found, the surrounding areas should be notified”), (2) ease of understanding (eg, “They need to tell us in simple words the results,” “Wish it could be explained more clearly by town officials,” “Will data from wastewater monitoring be made known to the public in easy-to-understand language?”), and (3) findings should be easy to access (eg, “Where do you find information like this in my community?”, “Finding the recent results quickly”). Respondents aged 50 to 59 years or ≥60 years were significantly more likely than those aged <50 years to mention public access to information in their responses (15 of 55 [27%] vs 9 of 104 [9%]) (χ² = 9.73; P = .002).

A few respondents were skeptical about government use of wastewater data (eg, “The government might ignore the results,” “‘Oh, we found x in the wastewater, cover it up until we have to tell someone,’” “I would wonder what viruses or bacteria there are that they do not tell the public”). However, most questions suggested that respondents did not know how findings would be used (eg, “Who is using the data and for what purpose?”, “What changes are actually done if the levels are too high?”, “Would high levels of shedded flu virus cause school or work shutdowns?”).

Protections Against Misuse of Wastewater Monitoring Data

Some respondents expressed concerns that data could identify specific households (eg, “No police state nonsense. No tracing and/or exposing the identity of any potentially infected humans”; “Wastewater monitoring almost seems like an invasion of privacy. I would want reassurance that there is no way that evidence can be traced back to the individual”). Other respondents wondered if wastewater findings could be used against certain neighborhoods, either neglecting them (eg, “Does the testing adhere to redlining, meaning underserved communities are underserved yet again?”) or stigmatizing them (eg, “My only concern is that the information could misrepresent a respective area”). Respondents aged ≥60 years were significantly more likely than those aged <60 years to express questions or concerns about fairness (5 of 31 [16%] vs 5 of 128 [4%]) (χ² = 6.33; P = .01).

Discussion

In our 5-state survey of racially and ethnically diverse adults, more than half had heard of wastewater monitoring, but nearly two-thirds knew little or nothing about it. Most survey respondents (80%) expressed support or strong support for wastewater monitoring.

The high level of public support, especially among Black, Hispanic, and rural respondents, extends findings from other studies that showed strong support for wastewater monitoring in less diverse samples.^8,12 Support for wastewater monitoring may have been cultivated by our brief, simple explanation in the survey instrument. Even among respondents who knew little or nothing about wastewater monitoring, 74% indicated support after reading a 2-sentence description of wastewater monitoring.

However, a low level of public knowledge about wastewater monitoring could pose a threat to public health. Individuals lacking knowledge about a health topic are more susceptible to misinformation about it. ¹⁷ With lack of knowledge, concerns about privacy, expressed by some respondents in our survey and other research, ¹⁸ could be an issue to stir opposition to wastewater monitoring. Women may be an especially important audience for increasing understanding. Women are more likely than men to make health-related decisions in families^19,20 and in our sample were less likely than men to be aware of wastewater monitoring and more likely to report knowing little or nothing about it.

Our analysis of questions and concerns about wastewater monitoring provided, to our knowledge, a first-of-its-kind look at public sentiments expressed by US adults on wastewater monitoring. Audience analysis is essential in health communication ²¹ for identifying beliefs, preferences, and gaps in knowledge that must be addressed to build public awareness and support. ²² Respondents generated many questions about the mechanics of wastewater monitoring, the accuracy of its results, and its cost and value. Questions about how findings from wastewater monitoring are used, by whom, and what actions are taken in response to the findings were also prominent. Answers to these questions, for the most part, have not been conveyed to the public in lay terms, ²³ if at all. Understanding is a foundational outcome for health communication, ²⁴ on which higher-order outcomes such as support often rely. ²⁵ Although communicating health information to the public is 1 of 10 essential services for local public health systems, it is generally an area of low capacity and underperformance.^26,27

We found a clear desire among respondents to have results easily accessible to the public in plain language. A 2023 review of public-facing wastewater data displays in 27 countries concluded that clear, consistent communication to the public and other nonscientific audiences such as policy makers and journalists was “urgently needed.” ²³ Even among people familiar with wastewater monitoring, most do not know how to access the findings in their community. ²⁸

Although privacy is a concern in discussions of how wastewater monitoring findings might be used, ¹⁸ fewer than 10% of comments from respondents expressed concerns or questions about privacy. The lack of privacy concerns may simply reflect how few panel members reported knowing a lot about wastewater monitoring; that is, people who have never thought about wastewater monitoring would not likely have questioned its application. Our findings align with this explanation: the more respondents reported knowing about wastewater monitoring, the more they expressed concerns about privacy. This explanation suggests that an unintended consequence of educating the public about wastewater monitoring could be creating more concerns about privacy. Given this possibility, public health communicators should proactively protect against privacy and ethical concerns by addressing them directly and explaining what protections are in place.

One objective of our research was to explore potential differences in public perceptions of wastewater monitoring across racial and ethnic groups and between rural and urban populations. We found few differences, and they were modest in size and/or inconsistent in direction. Knowledge gaps by race, education, or other socioeconomic indicators tend to emerge when new information enters a social system and access to that information is differential based on structural barriers. ²⁹ A possibility exists that, with so little public information currently available about wastewater monitoring, no group has any real disadvantage. Efforts to increase public communication about wastewater monitoring can reduce the likelihood of creating gaps by ensuring that new information reaches all groups across socioeconomic status.

Limitations

Our assessment was brief (4 items), and our sample, although geographically and demographically diverse, was not recruited to be representative of the communities from which it was drawn. We make no claims of generalizability to broader US populations.

Conclusions

We have 2 recommendations based on respondents’ questions and concerns.

First, local public health officials should proactively educate their communities about wastewater monitoring. At a minimum, these efforts should address the following:

1. how it works (eg, how it is performed, by whom, how often),

2. what the resulting data show,

3. how those data are used to protect the public, and

4. what protections are in place to ensure that individuals, schools, businesses, or neighborhoods are not identified or harmed by the data.

To ensure consistency in the way this information is conveyed across communities and to accelerate its uptake and spread, federal agencies could develop localizable information resources and distribute them widely.

Second, local information systems that rapidly share results with the communities whose wastewater was tested should be established. These systems cannot be data-heavy, jargon-filled maps and charts designed by and for scientists. Information must use plain language, be highly localized, convey unmistakable meaning in a simple way, and be actionable. When findings indicate elevated risk for areas of a community, active outreach should notify residents; simply posting information publicly is not sufficient.