Human norovirus is a major cause of gastroenteritis outbreaks from drinking water almost every year in the United States. This highly contagious virus enters the cell via a general virus uptake process: after it attaches on the surface of the cell, the virus enters the cell by the cellular process called endocytosis. Once inside the cell, the viral genome is released and the virus replicates in number, leading to illness. According to the data obtained from the dashboard for CDC’s National Outbreak Reporting System (NORS) and summarized in Table 1, hundreds of confirmed norovirus illnesses from drinking water occur almost every year in the United States. While this dashboard has data till 2018, it does not mean there has been no norovirus outbreaks from drinking water sources since then as norovirus outbreaks have occurred even after 2018 in the United States and continue to. Recent examples of norovirus outbreaks in the news include at health-care facilities and schools in Nebraska and at a restaurant in Washington. Both these cases did not identify the source of the norovirus infections probably because of legal or scientific reasons or both.
Nevertheless, Table 1 clearly points to the fact that norovirus is persistent in drinking water. A published study using data from previous years stated that norovirus illnesses cost the US economy more than $5.5 billion annually. Vaccines for norovirus are not currently available, though they are in development.
The data generated on the CDC’s NORS website from waterborne outbreak for the etiology virus and drinking water exposure pointed out to hepatitis A as another major virus besides the norovirus. Hepatitis A still occasionally contaminants drinking water as seen in Table 2, although vaccination is available for hepatitis A since 1996. Hepatitis A causes liver failure and is primarily transmitted from the discharge of infected people including from feces. When water containing this discharge runs off, it could contaminate other water sources including drinking water supplies and people who ingest the contaminated drinking water could get infected with hepatitis A. Table 2 points out that among the three cases of hepatitis A, two involved wells as the drinking water supply and both these wells were contaminated with hepatitis A. In the third case, the spring water used as the drinking water source was found contaminated with hepatitis A.
Contaminated wells used as the drinking water supply were also the main issue, occurring 50% of the time, for drinking water contamination with norovirus, Table 1. This was followed by septic tank issues and improper well constructions which did not meet local standards. The issues regarding septic tanks included a septic tank unable to handle increased sewage load, a leaching septic tank closely located to a well, septic tank backup, unmaintained septic tank overflowing and contaminating a well which was supplying the drinking water, and even an unpermitted septic tank. Some of these septic tank issues were also identified as the source of illnesses due to hepatitis A, Table 2. In a few cases in Table 1 that led to illnesses from norovirus, the contaminated water other than the well water included unsanitized ice and water dispensers, soda fountains that was cross-connected to contaminated pond water, and a microbially-contaminated garden hose that provided drinking water.
In addition to the norovirus and hepatitis A which are still a persistent concern in our drinking water to this day, there is a third virus of concern: sudden acute respiratory syndrome coronavirus-2 (SARS-CoV-2), found in both raw and treated wastewater in several places including in the United States. The concentration of SARS-CoV-2 genetic material in wastewater depends on the prevalence of the illness it causes, coronavirus disease 2019 (COVID-19). So the more COVID-19 illnesses there are in a community, the higher the concentration of SARS-CoV-2 genetic material in the wastewater treatment plant serving the community. SARS-CoV-2 gets in the water system from the feces, urine, and mucus of infected people and is detected in water in terms of its genetic material, specially the RNA. There are several data dashboards such as those operated by the CDC and the University of California MERCED to monitor the concentration of SARS-CoV-2 RNA in water to monitor the prevalence of COVID-19. While SARS-CoV-2 has not been detected in drinking water to date, it is imperative for wastewater treatment plants to be prepared for the future: if norovirus and hepatitis A are a current concern in our drinking water, then could SARS-CoV-2 and future pandemic viruses also be a concern in our drinking water?
Septic tank overflow leading to the contamination of wells used as the drinking water supply is a cause of norovirus and hepatitis A outbreaks, as discussed above, and also seen in Tables 1 and 2. This could also be a possible concern for the spread of COVID-19. The feces, urine, and mucus of COVID-19 infected people, when discharged into sinks and toilets, go into the septic tank and if the septic tank is unmaintained and overflows, the seepage from the septic tank containing the SARs-CoV-2 can get into the nearby wells and if these wells are used as the drinking water supplies, people who drink water supplied from these wells could get infected with SARS-CoV-2. While this scenario has not been reported, why could it not happen if it could cause norovirus and hepatitis A illnesses as shown in Tables 1 and 2?
There are federal and state guidelines for the distances between septic tanks and homes and also between septic tanks and wells. The CDC’s guidelines mention that a septic tank system should be 10 feet from the house and at least 50 feet from the water wells. The minimum 50 feet space between a septic tank and the water well is also recommended by the US EPA and by the states of Massachusetts and Nebraska. These guidelines should be followed to avoid the contamination of drinking water wells by the septic tank systems.
Some of the actions taken by the CDC to prevent future virus outbreaks includes offering education to affected homeowners about the risks of drinking water from private wells without disinfection, encouraging vaccination against hepatitis A, recommendations to bring water systems into compliance with environmental codes, and in one outbreak case, the contaminated facility was closed until the septic system, the cause of the outbreak, was in compliance with local codes. In other outbreak cases, the local and state government offices were encouraged to consider extending water utility services to the affected areas relying on the well water and in another, the investigation determined that the affected site could be reclassified from an individual water system to a public water system so that it could be regulated and maintained.
Our public water systems are federally regulated. The Safe Drinking Water Act (SDWA) (42 U.S.C.A. §§ 300f-300j-26) regulates contaminants in drinking water supplied by public water systems by requiring the US EPA to set standards. The maximum contaminant level for microorganisms in public water systems is ZERO (as stated in 40 CFR § 141.52). Several lawsuits have been filed for drinking water violations in regard to microbial contaminations. Recent examples include the USA v. City of NY and NY City Department of Environmental Protection for not complying with the required inactivation/removal of certain microorganisms and also the class action lawsuit filed by a family against a zipline attraction where an uninspected well contained norovirus and people got sick.
So lawsuits is an option to go the legal way to protect our public water systems. The SDWA citizen suit, similar to other environmental citizen suits, allows any person to commence a civil action in a US district court against any other person or government agency. There is a notice and delay period of 60 days and plaintiffs must satisfy federal standing requirements which means that the plaintiffs must show that they are affected in some ways by the drinking water violation. Specifically, they would need to show that the fear of being harmed by the drinking water is reasonable due to the defendant’s violation of the SDWA. Public water systems disclose reports to consumers that show exactly what contaminants and in what amounts come out of the consumer’s tap water and consumers could use this report to show which contaminant is at an illegal level to establish reasonable fear for the standing requirement.
The SDWA citizen suit is an effective way for us to achieve enforcement of the SDWA standards in public water systems and hence, to have safe, clean drinking water without disease-causing viruses in them. Public awareness is required to make people aware of the problems with virus contamination in their drinking water and to bring familiarity with the SDWA citizen suit.
Table 1: Prevalence of confirmed norovirus illnesses associated with drinking water in the United States during the past two decades. Links for data sources are provided in this table. Years not mentioned does not necessarily mean there were no norovirus cases, it could also mean no data was reported for that year.
|2000||July 2000: CA
June 2000: KS
June 2000: WVA
While epidemiological information could not point out water as a source of exposure, of the two wells containing fecal coliform and were a source of drinking water and located near a lagoon, one well was visibly contaminated.
Total # of norovirus cases: 356
Water source: Well for all three states
Type of water: Non-community for all three states
|2001||Jan 2001: WY
The three wells that served the lodge where people got sick were wither located in proximity to the septic tank or outhouse wells and grilled in fractured granite. The septic tank could not handle increased sewage load.
Sep 2001: WY
Total # of norovirus cases: 313
Drinking water source: Well in both cases
Water type: non-community in both cases.
|2002||Jul 2002: AZ
Jun 2002: CT
Jul 2002: NH
NH: Occurred at a camp setting where the drinking water source was from the well.
Total # norovirus cases: 414
Drinking water source: Well for all three states
Water type: Community for AZ, non-community for CT and NH.
|2004||Jul 2004: OH
Non-community and private wells substantially contaminated including with viruses. Possible factors for this contamination include on-site septic tanks, and cross-connection in the water distribution systems.
Jan 2004: PA
Total # norovirus cases: 1520
For OH: Mixed etiology including Campylobacter jejuni (bacterium), Giardia intestinalis (protozoa), and Norovirus
Drinking water source: Well for OH and pond for PA
Water type: non-community for both states
|2006||Jul 2006: MD
Dec 2006: OR
Jun 2006: WY
Total # norovirus cases: 335
For MD and WY: Norovirus strain GI
Also for WY: Norovirus strain G2 and Campylobacter jejuni (bacterium)
Drinking water source: well for all three states
Water type: Non-community for all three states
|2007||Jun 2007: CO & MD
Jan 2007: WA
May 2007: WI
Total # of norovirus cases: 432
CO and MD: Norovirus genogroup II
WI: multiple etiologies: Campylobacter, Salmonella (bacteria), norovirus genogroup I
Drinking water source: well for all four states
Water type: Noncommunity for all four states
|2008||June 2008: OK
Total # of norovirus cases: 62
Norovirus Genogroup I, strain GI.4
Drinking water source: well
Water type: Community
|2010||Jun 2010: CA
Total # of norovirus cases: 47
Drinking water source: Well
Water type: Non-community
|2012||Aug 2012: WI
Total # of norovirus cases: 19
Norovirus Genogroup I, strain GI.2
Drinking water source: Well
Water type: Transient, Non-community
|2014||Jul 2014: MO
Total # of norovirus cases: 62
Norovirus Genogroup II, strain GII.4 Sydney
Drinking water source: Well
Water type: Transient, non-community
AZ: No information available
Total # of norovirus cases: 102
Norovirus Genogroup I, strains: GI.3 and unknown
Drinking water source: Well in VA
Table 2: Prevalence of confirmed illnesses due to hepatitis A associated with drinking water in the United States. Links for data sources are provided in this table. Years not mentioned does not necessarily mean there were no norovirus cases, it could also mean no data was reported for that year.
|Month and year||States||Total # illnesses||Etiology and strain(s)||Drinking water source||Type of water system||Summary of what occurred|
|NC||16||Hepatitis A||Spring||Individual||Untreated spring water used as drinking water supply tested positive for Hepatitis A. Septic tank located directly upstream from the spring was potentially the contamination source.|
|TN||9||Hepatitis A||Well||Individual||One well tested positive for Hepatitis A. There was a faulty septic tank and likely the contamination source for the well supplying the drinking water.|
|Jul 2009||ME||2||Hepatitis A||Well||Individual||The septic system was breached and the seepage from the septic was contaminated with Hepatitis A. This septic system likely contaminated the well supplying the drinking water.|
Saleha Kuzniewski is an environmental scientist and has written extensively on a wide range of scientific subjects. A list of her recent publications in magazines is available at https://muckrack.com/saleha-kuzniewski