Wastewater as a Surveillance Tool to Identify the Prevalence of COVID-19 in Communities

With the current spread of the new Coronavirus, SARS-CoV-2 (COVID-19), the topic of finding new ways to protect public health is of vital concern and finding new ways to track the disease is imperative. The wastewater sector is beginning to answer the call and take the next step in furthering its protection of public health and the environment.

Many California wastewater agencies have begun testing influent wastewater for the COVID-19 virus as a means of understanding community outbreak and positioning along the curve. Taking advantage of Wastewater Based Epidemiology (WBE), testing for incidences of the COVID-19 in sewage, experts can determine whether the virus has been shed in the agency’s community, and if so, whether it is increasing or decreasing. Monitoring wastewater influent offers community and state leaders a unique set of data that can be used to evaluate if the virus is present in a community, even if individuals are asymptomatic. This data should be critical in determining where the virus is still presenting issues and areas where infection rates are declining. Testing influent wastewater can also be far more revealing of the community trends and is potentially much more cost effective.

Many CASA member agencies have elected to take part in influent testing to further efforts in understanding and tracking this new disease. CASA is aware of a variety of universities (e.g. University of Arizona, Stanford, University of South Carolina, UC Berkeley) and private labs (e.g. Biobot, CosmosID) offering such surveillance and we are working to understand the different methodologies, protocols, and costs associated with each. This new effort is a great example of how the wastewater sector is now, and always will be, a critical component to protecting public health. It is important to remember that these are still the preliminary stages of testing, and the wastewater sector will continue to do everything in its power to protect public health and the environment while providing an essential service.

CASA continues to support these efforts by coordinating with member agencies engaged in testing to share experiences, working with other associations and federal agencies to demonstrate value, and collaborating with researchers, academics and companies at the forefront of this testing effort.


Partner Publications
NACWA Releases White Paper for Clean Water Utilities Considering Epidemiological Surveillance of Wastewater for COVID-19


Orange County Register: Poop tests in sewage might predict coronavirus surge
State of Green Denmark: Analyzing wastewater can detect second wave of COVID-19 activity
E&E News: How sewage reveals ‘real numbers’ on scale of outbreak
CDM Smith: CDM Smith Launches R&D Effort to Predict COVID-19 Outbreaks via Wastewater Analysis
NY Times: https://www.nytimes.com/2020/05/01/science/coronavirus-sewage-monitoring-lockdown.html
Politico: https://www.politico.com/news/2020/05/01/cdc-human-waste-coronavirus-222253
Bloomberg: https://www.bloomberg.com/news/articles/2020-03-31/coronavirus-in-sewage-portended-covid-19-outbreak-in-dutch-city
Nature: https://www.nature.com/articles/d41586-020-00973-x
KQED: https://www.kqed.org/science/1963120/one-way-to-monitor-a-communitys-coronavirus-infections-raw-sewage
LA Times: https://www.latimes.com/california/story/2020-04-29/coronavirus-sewage-testing

Community Surveillance of Coronavirus in Wastewater

  1. CASA Coalition Letter to Bill and Melinda Gates Foundation
  2. CASA Coalition Letter to Rockefeller Foundation
  3. 6-2-20 CASA WBE Ltr CDC; 6-2-20 CASA Fact Sheet on WBE
  4. CDC Response to CASA Letter
  5. 07-23-20 Calapuig, Pablo – GoAigua – WBE for Spanish Government. Link to a webinar GoAigua did last Thursday with OneWaterAcademy, on the experience they have implemented in Spain, where they implemented a sewer surveillance system for 20+ cities, with 5+ million inhabitants, and 500+ sampling locations at a sewershed/neighborhood level:   https://attendee.gotowebinar.com/recording/5022048355643612417
  6. Sinclair, et al. – Pathogen Surveillance Through Monitoring of Sewer Systems – Argues that wastewater surveillance can identify pathogenic loads in a community prior to, and during, an outbreak.
  7. Barber G. – One Way to Potentially Track COVID-19: Sewage Surveillance. Wired 4/7/2020 – Stanford University under Dr. Alexandria Boehm are collecting wastewater samples from municipal agencies throughout the San Francisco Bay area. They are frozen in anticipation of future analyses to determine the level of presence of SARS-CoV-2 and to determine the community presence of the virus.
  8. Wu, F. et. al., SARS-CoV-2 Titers in Wastewater are Higher than Expected from Clinically Confirmed Cases. MEDRxIV 04/05/2020 – Analyzing wastewater influent at a large Massachusetts Wastewater Treatment plant for SARS-CoV-2 found it at higher levels than expected given the number of confirmed cases in the community. It may be an indicator that there are more cases which are undiagnosed in the population.
  9. The current spread of the new Coronavirus (SARS-CoV-2) which causes the COVID-19 disease is of pressing public health concern. The University of Arizona WEST Center is able to assist communities by testing for incidence of the Coronavirus in sewage.  Testing influent wastewater for the SARS-CoV-2 (COVID-19) virus is a pragmatic means of understanding community outbreak and positioning along the curve.  They are able to determine whether COVID-19 has been shed in your community and if so, what percentage of it remains viable.  Monitoring sewage can be used to evaluate if the virus is present in a community even if individuals are asymptomatic (i.e. show no visible symptoms).  It can also quantify potential risk of infection to wastewater workers. https://west.arizona.edu/news/2020/03/sewage-surveillance-west-tests-wastewater-determine-coronavirus-presence-communities
  10. Wastewater-based epidemiology may offer clues: EurekAlert reports that a new approach to monitoring coronavirus is being developed and refined. Know as wastewater-based epidemiology, the method mines sewage samples for vital clues about human health. In a new study, Arizona State University researchers analyze what can and cannot be measured when tracking SARS-CoV-2 in wastewater, and they highlight the economic advantages of the new approach over conventional disease testing and epidemiological surveillance.

Coronavirus fate in water, wastewater & sludge

  1. Environmental Science and Technology Letters – Silverman and Boehm; Review of Coronavirus Persistence
  2. Casanova L. and Weaver S – Inactivation of an Enveloped Surrogate Virus in Human Sewage; ES&T 2/23/15 – This article finds enveloped viruses are inactivated in wastewater at between 3 (30 deg C) and 7 (22 deg C) days depending on temperature. This indicates they would be very unlikely to survive mesophilic digestion (35 – 39 deg C at a minimum of 15 days).
  3. Gundy, Gerba, & Pepper December 3, 2008, Food & Environmental Virology:  Survival of Coronavirus in Wastewater – Found Enveloped Coronavirus are easily disinfected though they can remain viable for 2 – 4 days in wastewater
  4. Wigginton K., et al – Source and Fate of Pandemic Viruses in Urban Water Cycle – Environmental Science, Water Research & Technology – Examined inactivation rates and concluded that SARS or 2019-nCoV could make it to a WRRF in an infected form if the levels excreted in a community are high enough, especially in cooler climates.
  5. Ye, et al – Survivability, Partitioning & Recovery of Enveloped Viruses in Untreated Wastewater – ES & T – Optimized methods for enveloped virus recovery from wastewater.
  6. Pete DeMarco – Executive Vice President Advocacy and Research, online article – Coronavirus in Plumbing Systems: How did the Outbreak Occur in Hong Kong and is there a Risk in the United States. Explains how substandard plumbing systems in high rise dwellings could give rise to transmission of SARS-CoV.
  7. Bibby K. and Peccia J. – Identification of Viral Pathogen Diversity in Sewage Sludge by Metagenome Analysis; ES&T 1/24/2013 – This article identifies numerous strands of viruses in sewage sludge. It does not however, determine whether any of them are viable.
  8. Medema G., Ruijegers H., medRxiv preprint.  2020 What we learn about the Coronavirus through waste water treatment. – The authors look at wastewater treatment for the presence of SARS-CoV-2 at 7 cities and an airport in the Netherlands. Samples were taken at three different times, the first being three weeks before the first case was confirmed in the Netherlands. No detects were found in the first sampling and increasing presence was found in subsequent sampling. This is a good indication that surveillance of wastewater is a good indicator of community outbreak. Also no detects were found in treated effluent.
  9. Patricia Milner – USDA – Powerpoint Presentation – Composting in the time of COVID-19 – further confirmation that SARS-CoV-2 is inactivated rapidly at high temperatures, such as are used in compost.
  10. Casanova, L., Rutala, W. A., Weber, D. J., & Sobsey, M. D. (2009). Survival of surrogate coronaviruses in water. Water research, 43(7), 1893-1898. The article shows using two surrogate coronaviruses (TGEV and MHV) that coronaviruses can remain infectious in water and pasteurized wastewater for prolonged periods of time in the absence of disinfectants. The study also highlight coronavirus surrogate sensitivity to temperature changes, with higher survival at lower temperatures.
  11. Wigginton, K. R., & Boehm, A. B. (2020). Environmental Engineers and Scientists Have Important Roles to Play in Stemming Outbreaks and Pandemics Caused by Enveloped Viruses.
  12. EPA Expands Research on COVID-19 in the Environment: WASHINGTON (April 20, 2020) — The U.S. Environmental Protection Agency (EPA) continues to make COVID-19 issues a top priority. The Agency has been actively supporting response efforts across the country to protect public health. As part of these efforts, EPA Administrator Andrew Wheeler is asking for a rapid review with the Science Advisory Board (SAB) to provide feedback on research needs identified by EPA’s researchers. This research will enhance and build on the Agency’s capabilities to address the environmental and human health impacts from the virus that causes COVID-19.

Environmental Inactivation, Survival, and Transmission of Coronavirus

  1. Excellent fact sheet released by the California State Water Resources Control Board April 21 on the efficacy of wastewater and sludge treatment on inactivating the SARS-CoV-2 Virus.
  2. Sattar – Understanding the Environmental survival of Coronavirus – With the recent outbreak of the Wuhan coronavirus, infection prevention and control (IPAC) is an essential step in countering the spread of this virus. CREM Co’s Chief Scientific Officer, Dr. Syed A. Sattar, shares his insight on understanding the environmental survival and microbicide inactivation of coronaviruses in general for better IPAC. – https://www.cremco.ca/en-US/news/1044
  3. Wang, M. et. Al., Presumed Asymptomatic Carrier Transmission of COVID-19; Henen Provincial Peoples Hospital and Peoples Hospital of Zhengzhou University, Henen, China. 2/21/2020 American Medical Association. – New evidence for 2019-nCoV transmission within a family by an asymptomatic infected family member.  This suggests that asymptomatic but infected persons are a risk for transmission to others in close contact with them.
  4.  Marimuthu K., et. al., Air, Surface Environmental and Personal Protective Equipment (PPE) Contamination by Severe Acute Respiratory Syndrome Coronavirus (SARS-Cov-2) from a Symptomatic Patient; National Center for Infectious Diseases, Singapore, Published online 3/4/2020 American Medical Association ; Sampling of 3 hospital rooms of symptomatic patients of SARS-CoV-2 found positive results for one of them, though not on PPEs (other than one positive result on a shoe). No positive results after cleaning indicating that disinfection methods are effective.
  5. Chin, A., Chu, J., Perera, M., Hui, K., Yen, H. L., Chan, M., … & Poon, L. (2020). Stability of SARS-CoV-2 in different environmental conditions. The Lancet April 2020. The article highlights that COVID-19 virus can be stable under favourable conditions (transport medium at 4 C) but it is also susceptible to standard disinfection methods.
  6. Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents. Journal of Hospital Infection. This is a meta-analysis of 22 published papers on human and zoonotic coronaviruses that provides recommendations for surface disinfection practices that could be equally effective against COVID-19 virus. The paper recommends the use of 0.1% sodium hypochlorite and 62-71% ethanol for 1 min to disinfect frequently touched surfaces.
  7. van Doremalen, N., Bushmaker, T., Morris, D. H., Holbrook, M. G., Gamble, A., Williamson, B. N., … & Lloyd-Smith, J. O. (2020). Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New England Journal of Medicine. The article suggests that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days under experimental conditions in the laboratory.
  8. Water Research Australia: Fact Sheet

Environmental Fate of Coronavirus from Hospital Patients

  1. Xu & Xu – China CDC, 2/15/2020 – Isolation of 2019-nCoV from stool specimen of lab confirmed case of COVID-19 – A severely impacted patient with pneumonia and first onset on January 16th has a stool sample on February 1st and found clear evidence of 2019-nCoV which marked the first such finding.
  2. Zhang et. Al., Emerging Microbes & Infection, 2/17/2020 – Molecular and Serological Investigation of 2019-nCoV Infected Patients: Implications of Multiple Shedding Routes. – From Dr. Sobsey – The evidence of fecal matter and sewage as a contributing sources of transmission of this new CoV is still very limited and uncertain but certainly relevant.  Viral RNA has been detected in fecal specimens of some patients with diarrhea. See attached a more recent report in which viral RNA was detected in fecal samples (anal swabs) about as often as respiratory samples (oral swabs) of patients. This paper provides supporting evidence for possible enteris infection by this virus. Diarrhea occurs in 3-10% of hospitalized patients, based on 3 published studies.  The ability to cultivate infectious virus from a stool specimen has been reported only once so far and the concentration of the virus was not reported.  The extent to which fecal wastes and sewage from infected persons contains infectious virus and at what concentrations it may be present remains uncertain and is inadequately quantified. However, the documented presence of viral nucleic acid and infectious virus in fecal samples means that the fecal wastes and sewage of infected people needs to be managed on the basis of assuming it can contain this virus. In this respect, management of such fecal waste and sewage would probably need to be much the same as it was for Ebola virus and SARS.
  3. Xiao, F. et. Al., Evidence for Gastronomical Infection of SARS-CoV-2; Sun Yat-sen University, Zhuhai, Guangdong Province China – Testing of 73 hospital patients infected with SARS-CoV-2 found 53.5% were positive in stool with evidence of it in gastrointestinal tissue as well.
  4. Wolfer R. et. al., – Virological Assessment of Hospitalized Cases of Coronavirus 2019; Bundeswehr Institute of Microbiology, Munich, Germany 3/5/2020 – Found RNA of SARS-CoV-2 in throat, lung, and stool samples from 9 infected patients. However, infectious virus was readily isolated from throat and lung tissue but not from stool samples in spite of high virus RNA concentrations.
  5. Zhang, H. et. al., Can a Paper Based Device Trace SARS-CoV-2 with Wastewater Based Epidemiology. ES&T 4/11/2020. – This article considers the potential to use a simple test to detect the virus in wastewater.  The authors site a list of different diseases that have been detectable using rapid, easy systems in wastewater.  Rotavirus A uses a special piece of paper and the naked eye to get a positive.  Others like human papillomavirus use specially developed papers and smart phones.  Conclusions here are that the wastewater sector may be part of a solution to contain the virus.
  6. Wang, W., Xu, Y., Gao, R., Lu, R., Han, K., Wu, G., & Tan, W. (2020). Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Jama. This article is the second article to report the detection of live COVID-19 virus from the stool of two patients who did not have diarrhea. It highlights the potential transmission of COVID-19 virus via the fecal-oral route.

SARS-CoV-2 Analytical Methods

  1. Stephanie Pappas – Live Science – Online Publication 3/31/2020 – Coronavirus Testing is Ramping Up. Here are the New Tests and How they Work.
  2. Zhang, Y. et al. (2020a). Isolation of 2019-nCoV from a Stool Specimen of a Laboratory-Confirmed Case of the Coronavirus Disease 2019 (COVID-19)[J]. China CDC Weekly, 2020b, 2(8): 123-124. This article is one of only two publications that report the detection of live COVID-19 virus in patient stool specimens. It highlights the potential transmission of COVID-19 virus via the fecal-oral route