Flushing away privacy rights?

  • January 19, 2024
  • Lauren Daly


With the emergence of the COVID-19 pandemic, many new technologies that were relatively unknown and unused became important and have had continued primacy in public health surveillance; one such technology is wastewater surveillance. The regulatory design of Canadian privacy has been increasing allowances for intrusions on personal data for public health reasons. As this technology’s use continues to grow, courts will need to grapple with citizens’ privacy interests in their wastewater. This essay will analyze the current legal basis for privacy rights in Canada, the public health justifications for privacy infringement, and the potential conflicts that courts may see develop as this method of surveillance grows in popularity.

Wastewater surveillance uses wastewater treatment facilities to monitor and assess various biomarkers and substances in water samples flowing from the municipalities’ homes and businesses. Sensors in these facilities can be adapted to monitor substances related to drug and medicine use as well as general health information about the population.o solo el adc 1 Recently, this technology was most notably used to detect COVID-19 levels in the domestic population. This immediately triggered concerns from the public, media and bioethicists regarding the collection and dissemination of personal health data collected from waste samples.2 The newness of the technology, compounded with the uncertain legal implications regarding it, plunges this new style of civilian monitoring into the forefront of information privacy legal analysis.

Current uses of wastewater surveillance

While the use of wastewater to monitor public health and actions is relatively new, it builds upon existing public health surveillance infrastructure. The justifications for its use during the COVID-19 pandemic largely relied on public health justifications, especially considering low reporting rates, as well as asymptomatic transmissions. The information gained through the samples obtained from communities across Canada helped public health authorities to target their pandemic responses and better prepare for impending waves. It was critical in alerting public health authorities to incoming waves of the pandemic and helped to identify the prominence of new variants in the population.3 Its key benefit is that the results are not skewed, through the bias of only reporting those who consent and report their results, allowing even the most COVID-skeptic, and thus least likely to report their status, to be included in the sample.4 Currently, over 200 sites in Canada are conducting wastewater surveillance for examining COVID-19 levels in their populations.5 Its use has also been adopted internationally, and it is estimated that with international cooperation, 2.1 billion people could be monitored globally through sewage surveillance, demonstrating the scalability of this technology to become a tool of world-wide reconnaissance.6

Viruses and diseases are not the only markers that can be identified from sewage samples. This technology can also be used to monitor illicit drug use and identify the emergence of new designer drugs in the population. Currently, this technology is being used to analyze the population as a whole, and becoming especially popular in Europe, and to a lesser extent, the United States.7 The technology has even been expanded to determine the consumption of artificial sweeteners, therapeutic pharmaceuticals, and over-the-counter painkillers.8 The consumption of these respective products can be associated with socioeconomic downturns in tested communities.9 Thus, from these studies of wastewater, health officials can make choices regarding the services and help offered to these communities. The ability of this technology to monitor a variety of metrics, without the express consent of the population, and without judicial approval, allows for governments and public health authorities to quickly respond to emerging public health trends. These same metrics, however, have massive privacy implications, as prescription medication and daily habits such as diet are extremely personal and private to individuals.

One major concern with open access to sewage monitoring data is the concern that information about neighbourhoods, such as increased drug use in an area, could affect how various groups make decisions. For example, insurance companies may not wish to insure people in homes which test high for compounds associated with higher drug users, through making conclusions about the people who live in certain neighbourhoods.10 Even at the neighbourhood level, data relating to drugs and illegal activities could affect the market value of houses and be a reason to see investments in certain neighbourhoods as riskier. Communities can become vulnerable to stigmatization, especially in those communities that are already highly policed, who may feel increasingly targeted and persecuted.11 Marginalized communities are already subject to greater surveillance, and there have been concerns that surveillance technology can result in “social sorting,” a process which affects how marketing, police, and services are brought to communities.12 People who are on the municipal sewage system are not necessarily directly authorizing being part of this greater data analysis, raising important concerns over consent, and the inability of any community to choose to opt out of the system. The use of a method of constant surveillance targeting specific communities, even under the guise of public health and safety, at best feels paternalistic and at worst creates feelings of distrust and unease in relation to the government and law enforcement.

Concerns with this technology largely stem from its growing ability to move beyond population-level assessments, and to targeted analysis of individual buildings and neighbourhoods. The concern from bioethicists is that if biomarkers are available to be analyzed on an individual level, private information including diet, drug use, movement and location data could allow an extremely personal level of surveillance. Illegal drug creation wastes can also be tracked down to a specific source street, narrowing down police investigations. Future technologies are also aimed at using robots to track the source down to the specific emitting household.13 This concern isn’t nearly as outrageously science-fiction as it sounds—in both Hong Kong and Singapore, COVID-19 samples were combined with other data to track down possible cases to specific apartments. Health authorities were able to narrow in on two different homes containing positive markers for COVID-19, residing on two different floors of the same apartment building.14 If data could be traced to specific apartments, the public may have a greater privacy interest than what would have been obtained through anonymous population-wide data. The Canadian Water Network, a Canadian non-profit that advises policy-makers on water management, also acknowledged the emerging privacy concerns with wastewater testing, noting that “as the size of the population contributing to the sewage network being sampled decreases, the likelihood increases that surveillance results can be linked to small groups of individuals, creating a risk of their identity being disclosed”.15 Clearly, the time to legislate on this privacy issue has arrived.

Relationship of privacy law and public health in Canada

The collection of information by commercial private actors is currently ruled by the Personal Information Protection and Electronic Documents Act (PIPEDA) and by the government through the Charter, the Privacy Act and through statistical collections under the federal Statistics Act.16 PIPEDA specifically focuses on the protection of personal information and does not have robust protections for population-level privacy interests. Personal information under section 2 of PIPEDA is defined as closely linked to a human individual person; the information being obtained must be more than simply linked to an individual, but about an individual.17 It even extends to prescribing habits of doctors, despite what this may reveal about the community they serve.18 Thus, it is clearly established that individuals have very little ammunition in presuming privacy claims as a member of a population, even if the information collected was down to the community or neighbourhood level.

While legal ammunition is limited, there are valid concerns regarding population-level assessments for COVID-19 and other disease screenings. The data obtained through wastewater treatment had real impacts on the day-to-day habits of Canadians and the results may justify targeted actions limiting the mobility and privacy of people. Local populations can be targets of lockdowns and other measures to restrict movement when samples show an increase in COVID-19 variants in the water. These measures have massive constraints on individual liberty and when combined with the use of privacy-eroding surveillance data, the results seem dystopian. We currently do not know what level of infection justifies a lockdown other than the mandate that the measure must be “necessary and proportional.” Combined with the fact that wastewater surveillance can be constant and requires no ongoing justification for the government to conduct, such as outside a pandemic, is concerning for the respect of civil liberties.19 Wastewater analysis has continued to be conducted outside of the pandemic, and is unlikely to ever fully go away, since it is such a valuable tool to public health authorities. The public health justification for analysing the population in this way will be weaker once the COVID-19 threat is over, and outside of the pandemic the public may be less willing to have their privacy intruded on in this way.

Notably, even when a case involved specific, individualized personal information, courts have maintained a rule that public health is a valid reason for personal privacy violations. In Costa, Love, Badowich and Mandekic v. Seneca College of Applied Arts and Technology (2022), the court entered a judicial consideration for Charter violations relating to vaccination status, which failed with the court noting that the public interest in minimizing public risks of COVID-19 outweighed the applicant’s concerns regarding the vaccination policy.20 It has generally been held that while every case will require an analysis of the facts to determine the reasonableness of a privacy infringement, protection of public health weighs heavily in the favour of justifying state action.21 The justification for this finding is that public health empowers states “to restrict human freedoms and rights to achieve a collective good.”22 Projects using wastewater monitoring data to improve community public health services are likely to be covered under the blanket allowance for public health interests. The challenge associated with this standard is that the length to which personal freedom can be infringed for the collective good is unclear.

The boundaries of what constitutes public health is one of constant debate. One approach to defend using a public health justification is the “causal connection” test.23 This test states that if a causal connection between the problem and a widespread public health problem can be identified, it empowers governments to act as they see necessary, including violations of the Charter. The definition of public health has resulted in some advocates to include issues such as tobacco use, alcohol consumption and other personal choices under the umbrella of public health, justifying government actions to prevent harm to individuals or others. This logic has even been used to defend public health interventions for obesity, justifying the monitoring of diet and lifestyle choices in the population. It is unclear what falls under health, as it could be interpreted to include social and economic problems, as these have a causal connection to the health of the population.24 The concern with this broad and undefined limit to public health, when combined with the far-reaching monitoring of sewage data is that it can empower the government to continuously monitor the population as it sees fit. Since the sensors used can monitor anything from drug contents to disease, the powers of the public health doctrine allow for any agency to justify access to this data. While this data can be anonymized, the sheer scope of this type of surveillance on the general population should be one of concern, since the constant monitoring of people not accused of a crime goes against the section 8 Charter right protecting privacy from unreasonable search and seizure, is enshrined in the Constitution.25 Section 7 Charter rights are also at risk through this technology, under the protection of security of person, including privacy regarding information that could be released by the government.26

Ethicists justify using wastewater surveillance to monitor public health at the population level by arguing that when sample sizes are very large, the direct impact on any one individual is negligible. Concerns arise, however, when specific populations such as prisons, workplaces or schools are the targets of surveillance. Even when samples are taken and analyzed only at the population level, there are concerns that the findings could stigmatize the whole community or result in punitive restrictions, such as reducing visitors in prisons, across the board.27 While these consequences can also result from other forms of surveillance, nothing can compare to the scope and depth of monitoring possible with sewage analysis. Since sewage analysis can reveal information relating to personal habits, DNA contents and movements, the information within is more revealing than traditional stationary cameras and the like. While these policies are justified with the argument that it is less invasive than individual drug testing, this argument doesn’t carry enough weight. Consent is generally required at either the start of employment or at the time of testing, which is removed when wastewater analysis occurs. Consent is a foundational principle underlying many regulatory regimes, including PIPEDA.28 All individuals are also subject to the collection and examination, whether or not they have been suspected of a crime, and it is impossible to opt out of the system. The limits of when and where this surveillance can occur, and under what circumstances it is justified, has failed to be clearly determined.

Use of sewage data in legal proceedings with individuals

There has yet to be a Canadian court challenge to the use of sewage data in a legal proceeding, dealing with one accused, outside of its use in the public health context. There has, however, been adjacent legal discourse which can illuminate how courts may view this issue in the future. First, it is pertinent to determine if flushed materials would be considered personal data under PIPEDA or other relevant legislation. Personal information is defined as “information about an identifiable individual” under PIPEDA section 2, and as previously established, the information obtained from sewage collection can contain individual drug use and movement habits, either through being a single resident of a home or through the identification of personal biomarkers.29 Indeed, the concern for individual-level identification through sewage is so established that bioethicists have advised that individual names could be identified using it, requiring a higher level of security under Guideline 11 of the World Health Organization guidelines for public health surveillance.30 It is most likely that if there is a clear path to establishing that there is a personal interest in sewage contents it would have to be established that the data is specific about one person. This argument would be the easiest to make when the sample it is traced to a single occupancy household, or if technology using individual specific biomarkers continues to grow. Information regarding drug use or movements, as considered by researchers, would interact most strongly with the information protected under the Privacy Act and PIPEDA.31

Even if the data obtained from sewage surveillance alone isn’t enough to establish an identifiable link to one person, it may be used in an aggregate of sources to do so. This “surveillance mosaic” could combine metadata from sewage with other sources to create an identity portfolio, the parts of which may not engage personal privacy, but the aggregate of which does. As Ivan Škorvánek et al. point out in their study of sewage surveillance,

Thus, for instance, sewage monitoring revealing details about frequency of toilet use, or consumption of certain drugs, combined with monitoring of phone records or location data revealing contacts with medical professionals, could allow more specific inferences to be made about the health status of the person under surveillance than application of only one of these measures. This is recognized in the so-called “mosaic theory,” developed in US case-law and doctrine, which holds that the putting together of a sufficient number of pieces of information that in themselves reveal little or nothing of someone’s private life (mosaic stones), may result in a picture (the mosaic) that is quite revealing32

The mosaic theory has been accepted as a valid concern regarding national security concerns, with the Federal Court of Canada acknowledging that the mosaic theory is an accepted concept in deciding if a piece of information has national security connections.33 This theory has yet to be extended however to personal information in a privacy sense, however this may be the natural continuance in Canadian legal doctrine. In the United States, the mosaic theory has been accepted as applicable to personal security information, with the court noting that data such as movements and health information can be aggregated to reveal more than what would have been determined by each individual piece in isolation. In this case, the court was concerned with aggregate movement data.34 Since it has been noted that biomarkers in sewage could be used to determine individual movements, the mosaic theory is of direct interest to Canadian lawmakers in their analysis prior to making decisions.35 Currently, the uncertainty of where Canadian courts fall on this issue creates a barrier to clear legal rights regarding sewage privacy.

Further barriers to establishing sufficient personal interest in sewage information is the fact that much of the data is anonymous. Aside from individual biomarkers, which are a separate concern, much of the data collected is only narrowed to the household level. It is difficult, therefore, to establish in a multi-person household, that any one person is responsible for the compounds detectable in waste. In this way, the samples are automatically anonymized through the challenges posed by the sample collection. The UK considered a case in which a privacy interest was expressed in anonymized information and held that when information is properly anonymized, there is no longer an individual privacy interest claim to it.36 It is unclear where the Canadian courts will fall on this, as in the Supreme Court of Canada case, British Columbia v Phillip Morris International (2018), the court ruled that public health databases, even if they contained anonymized public health information, weren’t compellable in court.37 Clearly, anonymous health information still, therefore, has some level of privacy interest attached. Canadian scholars have theorized that the best approach may be to weigh the public utility, of research and other proper uses, and the privacy interest a person may have in the data they are a part of. These competing interests should weigh on courts when considering whether to grant access to anonymous health records without the consent of the individuals who comprise it.38

The personal nature of data obtained through sewage monitoring also closely interacts with section 8 of the Charter, as the seizure of biological or other personal information, through wastewater monitoring, in criminal proceedings may be used to identify or incriminate an individual.39 When addressing non-anonymized data within sewage, the data can be traced back to specific households or individuals using biomarkers and sensors. Since section 8 of the Charter is protecting against unreasonable search and seizure, the seizure would have to be found to be unreasonable. Outside of judicial approval, the analysis turns to if one has a reasonable expectation of privacy in your household effluents. So, the key concern is if the courts do consider the contents of sewage to be an abandoned privacy interest, in which one has no expectation of the security of personal information. Canadian courts considered the privacy interest in the garbage in R v Patrick, whereby the courts considered if the defendant, in that case, had a reasonable expectation of privacy in the contents of his garbage, and subsequently, if the seizure was lawful. Crucially, the court, in that case, held that the privacy interest in garbage placed on the curb no longer carried a privacy interest within it. The logic was that by placing it on the curb for collection, the defendant surrendered control over the contents, and was essentially allowing any passerby to access it.40 As a result, his section 8 Charter rights, the right to reasonable search and seizure, were not violated.41 The question remains regarding how the courts would treat sewage waste. On one hand, the action of disposing sewage is similar to taking trash out of the house, in that you intentionally dispose of and fail to continue to monitor the removal of waste from the house. Many people do not continue to think of maintaining privacy of their sewage, and prefer to just “flush it away.” It would be a stretch, however, to contend that garbage and sewage disposal interact with privacy rights in the same way. First, it is notable that in R v Patrick, a key reason behind the decision to deem garbage as outside of individual privacy interest was the fact that the garbage was freely accessible to the public, and abandoned. On the contrary, there is no expectation that the general public has access to their sewage water or the technology used to analyzed it. Garbage collection is very visible, and so people could in theory monitor who is collecting their trash, if they had an interest in doing so. There is no comparable way to do this with wastewaters. In this way, the court’s finding in Patrick does not hold the same strength in a finding for reasonable search and seizure of sewage water. Strength for the argument in a continued interest in “abandoned” sewage water can be found in Justice Abella’s dissent in Patrick, where she notes that abandonment does not mean the abandonment of privacy interest in waste, as one expects collected garbage to continue to their expected destination.42 In the case of sewage monitoring, a flush does not create an abandonment of the information contained within it, but the expectation that it will be cleaned and processed, but not analyzed for incriminating information. When one considers the concept of a septic tank, the idea of abandoned privacy interests becomes murky. The wastes contained in a septic tank are specific to one household, and if that household is single occupancy, one person. Its collection is done by private companies, and most people do not consider this to be a security risk, or an abandonment of their privacy interest. If a private organization hired septic company to test their client’s wastes, would this engage their privacy interests? Can the police elicit the cooperation of private companies during their investigation to turn over sewage samples obtained from a target household? Thus, the current theories of waste and abandoning privacy rights is not so neatly sorted when considering sewage surveillance. The idea that septic tank sewage analysis would present considerable ethical concerns was even contemplated by the Canadian Water Network.43 An analysis of the legalities of seizing waste from utility companies will be discussed in the proceeding paragraphs.

Further issues with sewage compared to garbage is limitations on control of disposal. Individuals concerned with the privacy of their municipal waste can take steps to ensure that it is less accessible, including shredding documents, obscuring information, and holding onto sensitive garbage until just before the disposal team arrives or driving it to a dump themselves. There are no such comparable alternatives for controlling their sewage wastes. The water treatment system removes much of the control of their wastewater information from individuals and places the responsibility for privacy in the hands of the government and treatment plants. Scholars have pointed out that in the USA, with 80% of homes connected to the sewage system, any police surveillance done through sewage monitoring would be inescapable.44 Thus, the current precedent for garbage disposal is not easily applied to sewage monitoring privacy concerns.

This issue of abandoning privacy interests has been looked at in regard to DNA collection by police. In D’Amico v R (2019), the court found that the accused had abandoned his privacy interest in his DNA when he left behind a coffee cup he had drank from.45 While the court did note that one cannot simply abandon their privacy in the interest in DNA through the abandonment of a physical item, the court still held there was no breach of Charter rights since the collection was non-intrusive and it was only studied for comparison with an index of other samples, not an in-depth dive into the information within the DNA. Justice Ruel did note, however, that the accused “knew or should have known that leaving bodily substances in public could eventually allow law enforcement to collect and analyze his DNA for comparative purposes”.46 Clearly, the court feels that actions that leave bodily fluids in public are free for collection by police for comparative purposes. In this way, public restrooms and the collection of wastewater at public places could be considered open season for DNA collection. Especially considering that the concerns regarding the home and privacy interests in private residences, collection at public places would allow for easily accessible DNA samples. Combined with traditional surveillance technology such as cameras, the police would be able to set up public restrooms for DNA collection purposes without the public even knowing they could be waiving privacy interests. An Ontario case sets a different precedent than that observed in D’Amico, as in R v Bhogal (2020), the court considered a glass used by the accused that the police later used to obtain DNA from, was a seizure, the DNA was not abandoned, and contained a privacy interest. The court considered a vast quantity of existing Canadian jurisprudence in common to this decision, including the D’Amico decision, but found that “A search of the glass to secure the biological material containing DNA was an invasion of informational (and, in a remote sense, bodily) privacy.”47 However, the court did allow for police to seize samples when they have reasonable grounds to believe that the DNA within will lead to a crime scene sample, and said that the police can instead apply for a DNA warrant after the fact to analyze the sample. As a result, the court held that obtaining a DNA profile from a publicly seized sample would be a breach of the Charter. It is notable, however, that since this decision is in direct contradiction to existing jurisprudence, and the police acted in good faith, the DNA sample was included in the trial.48 The courts of Canada have thus created a murky police precedent, as the inclusion of seized DNA from public sources has not been tried at the Supreme Court level. It is unclear if the seizure of DNA from wastewater sources would follow the Quebec or Ontario precedents at the federal and superior court levels.

There is also ambiguity regarding the fact that sewage monitoring currently is done just outside the home, typically at treatment plants. The strongest protections are granted to within people’s homes and on the physical person. Since a lot of the monitoring is conducted outside the property of interest, the property interest is less robustly protected. Even collection of data a short distance away, such as what could be done at the neighbourhood level or on the same street, doesn’t trigger the same level of protection.49 In R v Gomboc (2010), the Supreme Court of Canada held that the collection of electricity usage information from a station down the road from the accused’s house did not engage his privacy interests.50 They also noted that the consumption information gained by the utility company was not personal enough to engage a privacy interest. This once again harkens back to the “mosaic theory” in privacy law, and it appears here that that theory was not engaged in the discussion. It was also considered that since the accused had not followed the requirements of regulations in establishing that they wished to maintain a high confidentially of their usage reports with their supplier, the court additionally considered an insufficient expectation of privacy. The dissent in this case, however, offers an interesting point, which is that one does not authorize the police to enter homes, through the conscription of utility providers, either physically or through technology, to gain information about the home without a warrant. The dissent, therefore, considered warrantless collection of utility information to be a breach of section 8 Charter rights.51

Unfortunately, this ruling still fails to offer an unequivocal stance from the court on the use of utility information. One factor the majority held in large esteem was that electricity usage information was not personal, but this is likely to be found differently for wastewater. Since wastewater can show indicators of private drug use and other medical information, the information dealt with by wastewater monitoring systems is more intimate. The arguments offered by the defence may, therefore, have a greater pull regarding sewage monitoring.

As previously mentioned, the technology of sewage monitoring would be abundantly more revealing if the water that was analyzed was seized from the septic tank of one property. The police can then enlist the help of a septic tank pumping company to obtain samples for testing. In 2017, the Ontario Court of Appeal distinguished from the decision in Gombac, and held that hydroelectric usage data requires a warrant for police to possess.52 The justice in that case, R v Todd-Hurst (2016), distinguished their facts from those in R v Gomboc stating that since the police only used the electricity data in Gomboc to confirm their suspicions, rather than begin and base their case around the utility data, a warrant should have been obtained in this case to secure it.53 This seems like an arbitrary distinction and is likely to create uncertainty in police search conduct. This unclarity may justify obtaining the information regardless of obtaining a warrant since they can claim they obtained it in good faith application of earlier laws. This case may have even weaker protections in the wastewater surveillance context, since a utility company disposing of sewage wastes is not revealing anything about usage data, but instead is just handing over sampled wastes to the police.

Another case which offers insight into how a court may hold one day is the case of R v Tessling, whereby the court held that thermal imaging of a home by police without a warrant is lawful, and not a violation of personal privacy. In that case, thermal imaging cameras were used to view suspected properties by police. The Supreme Court considered whether the use of thermal imaging technology, conducted off the property of the accused, is a violation of section 8 Charter rights. The majority held that the accused did not have a reasonable expectation of privacy in the heat emissions of their house, and the heat signatures did not reveal intimate information about the accused. As a result, the court found that section 8 rights were not violated.54 It is interesting that technologies such as thermal imaging are not considered to be covered by personal privacy interests, and this too suggests that other emanations from the house, such as sewer water, would not interact with the “core” of personal information either, especially if there are multiple occupants of the home and the data is relatively anonymous. Sewage data such as output timing, the volume of materials and other macro data analysis are more akin to the usage data and heat signature data that was observed in the above cases. Therefore, the data relating to usage of the sewer system is likely to be the least protected data in the context of wastewater surveillance. Courts may, however, distinguish qualitative data, such as disease and drug use, from these cases since this is information that is more personal and identifying.

One way that could limit the impact on the civil liberties of the accused in connection to wastewater surveillance is by requiring a warrant to be obtained before placing sensors near the homes of suspects. This would limit the type of data that can be obtained at a personal level and result in greater discretion when using this technology, a requirement which is likely to become more important as the specificity and abilities of sewage sensors continue to improve. Currently, the only barrier to using wastewater analysis in a meaningful way in criminal cases is the cost and practicality of attempting to monitor a single household’s sewage output.55 This barrier may become increasingly thin, however, as technologies improve. It has also been suggested that police should need warrants to obtain usage information from utility companies, and this could be extended to include samples from wastewater collection companies as well, especially in the septic tank context. A move to make all utility information require a warrant would be in line with the current requirement that police obtain a warrant before obtaining telecommunications data from service providers. This follows emerging jurisprudence requiring warrants for telecommunications data and mandating that telecommunication companies have an obligation to keep their subscriber’s information private.56 Similar expectations for septic pumping service suppliers could be an avenue of privacy protection, especially if these companies begin to test their customers' samples. Extending this expectation of privacy to sewage water information would be a victory for privacy protection.

To govern wastewater surveillance, jurisprudence or legislation needs to exist to minimize the risks of a Section 8 Charter violation and mitigate against privacy intruding harms. It is hypothesized that general trends in sewage water, such as drug levels and other contaminants that are not of a personal source such as DNA, are unlikely to be protected under s.8 protections in the Charter, as seen in R v Tessling, and R v Gombac.57 It is more likely that any protections given to the individual would be limited to when DNA is obtained from the sample, however, the warrant requirements in each province is still unclear, and it is yet to be definitively decided on. The decisions in both R v Bhogal and D’Amico suggest that police are permitted to collect “discarded” DNA, possibly including sewage sources, and can later apply in good faith for a warrant.58 The resulting body of jurisprudence shows that Canadians have very little claim to the information contained in their wastewater and that their right to privacy for waste and other emissions from their house is not currently well protected by existing privacy laws. Canadian courts also appear to be at an impasse as to how information collected by service providers and utility companies should be treated in evidence, and if the data obtained through these sources carry a reasonable expectation of privacy.


The concept of waste and the abandonment of privacy rights demands rethinking in the 21st century. The current conception of waste and the abandonment of privacy interests in disposed materials does not align with the personal nature of the materials that are disposed of through sewage. The specificity of data obtained from wastewater samples will advance as technology advances. It is important to state that the uses currently employed in Canada have clear public good, and it is unlikely that a complete erasure of the system is not likely, possible, or optimal. However, lower courts are setting up precedents that allow for the collection of vast quantities of information about the public without their consent, knowledge, and without accusations of a crime committed. There is no apparent boundary to what is reasonably connected to a public health justification for privacy infringement, and this uncertainty could be exposing Canadians to overly invasive and paternalistic surveillance.

It is also unclear which conception of “abandoning” privacy interests, especially in the context of abandoning DNA information, the Supreme Court will acknowledge. There is clear support in the judiciary for both laws that support the requiring warrants for police to obtain utility and service provider data, but there is also a considerable body of jurisprudence that holds the opposite. The extent to which private companies are conducting sewage surveillance with septic tank samples is unknown and could provide greater avenues for information gathering by police in the future. As technology continues to improve, wastewater surveillance has the capability to become a source of inescapable surveillance thought only possible in fiction. The biggest concern is the use of technology in the future to carry out targeted and biomarker-specific monitoring of individuals, and the use of the information received in court proceedings. Technological advances such as tracking robots and DNA-specific sensors demand more vigorous data governance regimes. Legislatures must act now to secure civil liberties and prevent the Orwellian descent into the erasure of personal privacy. This paper did not analyze the use of sewage data in tort cases, as private cases are less likely to have access to this information. However, further analysis may be required to determine the boundaries of using this information in tort cases if this information becomes increasingly publicized.


Lauren Daly is a teaching assistant at Queen’s University Faculty of Law.


1 Bart Van Der Sloot, “Truth from the sewage: are we flushing privacy down the drain? (2021) 12:3 European Journal of Law and Technology (WestLaw)

2 Johnathan Ore, “Wastewater surveillance provides crucial COVID data, but also carries privacy concerns: scientists” (May 29, 2022), Online: CBC

3 Bio-Rad, “How can we track new SARS-CoV-2 Variants in Real-Time?” Online: BioRad

4 Katherine DeClerq, “What Is Wastewater and What Is It Telling Us about Covid-19 in Ontario?” (13 April, 2022), Online: CP24

5 Douglas G Manuel, et al. “The role of wastewater testing for SARS-CoV-2 surveillance.” (26 August, 2021) 2(40) Science Briefs of Ontario COVID-19 Science Advisory Table (ResearchGate)

6 Olga Hart, and Rolf Halden, “Computational analysis of SARS-CoV-2/COVID-19 surveillance by water-based epidemiology locally and globally: Feasibility, economy, opportunities and challenges” (15 August, 2020) 15 Science of the Total Environment 138875 (Elsevier)

7 Christian Daughton. "Monitoring Wastewater for Assessing Community Health: Sewage Chemical-Information Mining (SCIM)." (2018) 619-620 Science of The Total Environment 748-764 (Elsevier)

8 Dung Phung, et al. “Can wastewater-based epidemiology be used to evaluate the health impact of temperature?—an exploratory study in an Australian population” (2017) 156 Environ. Res., 113-119 (Elsevier)

9 Nikolaos Thomaidis, et al. “Reflection of socio-economic changes in wastewater: licit and illicit drug use patterns.” (2016) 50:18 Environ. Sci. Technol., 10065-10072 (ACS Publications)

10 Supra 1

11 Teresa Scassa,Pamela Robinson, & Ryan Mosoff. "The Datafication of Wastewater: Legal, Ethical and Civic Considerations." (2022) 2022 Technology and Regulation 23 (GoogleScholar)

12 David Lyon, ”Surveillance, Security and Social Sorting: Emerging Research Priorities” (2007) 17:3 International criminal justice review 161–170 (Heinonline)

13 Supra 1

14 Judith Chui Ching Wong, et al., "Non-intrusive wastewater surveillance for monitoring of a residential building for COVID-19 cases." (2021) 786 Science of The Total Environment 147419

15 André Corriveau, et al., “Canadian Coalition on Wastewater Related COVID19 Research” (September 2020) at 9, online (pdf)

16 Personal Information Protection and Electronic Documents Act (PIPEDA) SC 2000 c.5 PIPEDA]., and Statistics Act, RSC 1985 c. S-19., and Elaine Gibson, “Public Health Information” Ch. 4 in Bailey et. Al (eds) Public Health Law & Policy in Canada (2nd ed) (2008: LexisNexis)

17 Personal Information Protection and Electronic Documents Act, SC 2000, c 5.

18 Canada, Office of the Privacy Commissioner of Canada, Privacy Commissioner publishes his finding on the prescribing patterns of doctors, (PIPEDA Case Summary #2001-15) (Ottawa: Office of the Privacy Commissioner of Canada, 02 October, 2001)

19 9 Kalman Samuels-Team. “What Legal Right Does the Government Have for Covid 19 Restrictions?” (26 July, 2022) online: Kalman Samuels

20 Costa, Love, Badowich and Mandekic v. Seneca College of Applied Arts and Technology, 2022 ONSC 5111 at para 110 Costa

21 Supra, 9

22 Lawrence O. Gostin, “A Theory and Definition of Public Health Law” (2000) 10 J. Health Care L. & Policy

23 Mark Hall, “The scope and limits of public health law.” (2003) 46:3 Perspectives in Biology and Medicine S199-S209

24 Ibid

25 Canadian Charter of Rights and Freedoms, s 7, Part 1 of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c 11 s. 8 Charter]

26 Ibid Charter, and Mary Bryant, “Constitutional Law- Right to Life, Liberty and Security of Person” (07 May, 2015) Online: WestLaw

27 Wayne Hall, et al., “An analysis of ethical issues in using wastewater analysis to monitor illicit drug use.” (2012) 107:10 Addiction 1770

28 Supra 16, PIPEDA s.6

29 Supra 16, PIPEDA

30 Steve Hrudey, et al., "Ethics guidance for environmental scientists engaged in surveillance of wastewater for SARS-CoV-2."(2021) 55:13 Environmental science & technology 8484-8491 (QL)

31 Supra 1, 16, and Privacy Act, S.C., 1985, c. P-21

32 Ivan Škorvánek, Bert-Jaap Koops, & Tjerk Timan. “Surveillance, Criminal Procedure, and Regulatory Connection: the Case of Sewage Monitoring.” (2019) Tilburg Law School Research Paper Forthcoming 12

33 Canada (Attorney General) v. Huang, [2018] F.C.J. No. 589 at para 15

34 United States v. Maynard, 615 F.3d 544 (D.C.Cir. 2010) at paras 562-563

35 Supra 1

36 Regina v The Department of Health, ex parte Source Informatics Limited, [2001] QB 423, [1999] EWCA Civ 3011

37 British Columbia v Phillip Morris International Inc ,(2018) SCC 36

38 Elaine Gibson, “Is there a privacy interest in anonymized personal health information?” (2003) Health Law Journal at 97

39 Supra 24, Charter

40 R. v. Patrick, (2009) SCC 17

41 Supra 24, Charter

42 Supra 37, at para. 76

43 Supra 14, at 9

44 Supra 10, at 28

45 D’Amico v R (2019) QCCA 77

46 Supra 42, at para 379

47 R v Bhogal (2020) O.J. No. 5999, at para 92

48 Ibid, at paras. 123, 131

49 Supra 10

50 R v Gomboc, (2010) SCC 55

51 Ibid

52 R v Todd-Hurst, (2016) ONCJ 159

53 Supra 47

54 R v Tessling, 2003 SCCA No 116

55 Supra 25

56 Michael Geist, “Why Your Telecom Must Defend Your Right to Privacy: Geist.” Toronto Star (25 January, 2016), Online: thestar.com

57 Supra 47 and 51

58 Supra 44 and 42