Wastewater-Based Epidemiology Program

About the Program

Washington Wastewater-Based Epidemiology (WAWBE) program started in collaboration with the Centers for Disease Control and Prevention’s National Wastewater Surveillance System (CDC NWSS) to monitor COVID-19 at a community level. WAWBE works with local health jurisdictions (LHJs) and wastewater treatment facilities across the state to test wastewater samples for SARS-CoV-2, the virus that causes COVID-19. This data can help state and local health departments monitor trends and gain a sense of community COVID-19 levels.

What is wastewater-based epidemiology?

Wastewater-based epidemiology is measuring a pathogen’s levels in wastewater. To do this, we collect samples of untreated wastewater at wastewater treatment plant over a 24-hour period. The wastewater sample can then be tested for pathogens, including COVID-19. This sample can inform us on community-level infection trends. 

Why is wastewater-based epidemiology useful for COVID-19 response?

It is often not feasible to conduct individual clinical tests on an entire population due to capacity limitations and individual testing hesitancy. Approximately 40% of people with COVID-19, both asymptomatic and symptomatic cases, shed virus RNA in their stool. With the increase in at-home testing and decreased masking requirements, wastewater data has potential to provide better insight into community spread of COVID-19 when paired with case data. Therefore, wastewater results can complement other surveillance sources, such as clinical testing and hospitalization data. Wastewater can also be used as a leading indicator, that reveal increases in community infection rates in the wastewater 3-5 days before clinical testing, depending on the COVID-19 variant.

Limitations of Wastewater-based Epidemiology in Monitoring COVID-19

Wastewater sampling for COVID-19 is a relatively new tool and we are still working to understand how the data can be applied to public health action. Right now, it is too early to know if increases in wastewater COVID samples will result in increased reported cases. Watching sustained increases is key with other data to inform decisions. Because each sewer shed is unique to that community, there is currently no clear way to directly compare virus levels across sewer sheds even when using the sample collection and analysis methods. 

How is the data stored and secured? 

Wastewater data that is uploaded to an internal DOH database called REDCap. The system is available to Department of Health epidemiologists for analysis. After our epidemiologists analyze the data, they upload it to CDC’s DCIPHER data storage. DCIPHER is a secure platform that is internal to the CDC. This data is then displayed on the CDC COVID Data Tracker. Communities that consist of <3,000 people do not appear on the COVID data tracker.  

Who are the current sampling participants?

As of August 8, 2022, 21 wastewater treatment plants across 10 counties are participating in wastewater-based epidemiology for COVID-19. Current sampling counties include Benton, Chelan, Clark, Franklin, Grant, Jefferson, King, Pierce, Snohomish, and Spokane. 

How Data is Shared

DOH recognizes the importance of using all data sources to develop a complete picture of COVID-19 activity in Washington. DOH currently has results for all facilities that are participating in wastewater sampling and testing via the WAWBE and CDC NWSS program. Additionally, each LHJ and wastewater treatment plant receives results data in real-time as well as through other reports. DOH is working with each LHJ to track wastewater results and determine how to incorporate the tool into their respective response plans. 

Wastewater Data and Privacy

The WAWBE program currently uses wastewater samples collected at wastewater treatment plants over a 24-hour period. As a result, the sample is representative of the overall community that contributes waste to that treatment plant. By collecting at the wastewater treatment plant, there is no way to know who contributed to the sample.

Funding for WAWBE Program

The WAWBE program is funded through 2023 by two CDC grants: Expanding Laboratory Capacity and Enhancing Detection Expansion. All states must apply annually for funding. 

Washington Wastewater-Based Epidemiology Team 

The Washington Wastewater-Based Epidemiology (WAWBE) program is a collaborative effort between several programs within DOH, including Environmental Public Health Sciences, Surveillance Epidemiology, and Microbiology. For inquiries about the program or more information please contact us at WastewaterBasedEpi@doh.wa.gov.

More Resources

CDC Data Tracker

Wastewater-Based Epidemiology Frequently Asked Questions, Network of Wastewater-Based Epidemiology

Benton-Franklin Health District COVID-19 Dashboard

Washington Tracking Network