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Maryland Department of the Environment

Maryland launches targeted wastewater sampling for coronavirus


COVID-19 Sewer Sentinel Initiative builds on success of science-based, field-tested pilot program, moves to provide data to detect and respond to outbreaks in vulnerable communities


BALTIMORE (Nov. 12, 2020)– Governor Larry Hogan today announced a statewide initiative to sample wastewater as an early warning system of a COVID-19 outbreak in vulnerable Maryland communities.

As part of Maryland’s COVID-19 Sewer Sentinel Initiative, Governor Hogan has approved funding of $1 million to sample wastewater for the virus that causes COVID-19 in congregate living settings. The Maryland Department of the Environment (MDE), in close coordination with the Maryland Department of Health (MDH), will lead the testing effort. 

“Our administration is setting an example for the nation on how states can use cutting-edge science, innovative technology, and local partnerships to protect public health and help combat a second wave of COVID-19 infections,” said Governor Hogan. 

“Our COVID-19 Sewer Sentinel Initiative can provide early detection, which can save lives. Wastewater can tell a lot about the health and well being of communities and watersheds,” said Maryland Environment Secretary Ben Grumbles.

“This program will help us to understand community transmission in areas and congregate settings,” said Maryland Health Secretary Robert R. Neall. “Used thoughtfully, it will help us focus our prevention and testing efforts where they are most urgently needed.”

This next phase of the Sewer Sentinel Initiative builds upon information obtained during a pilot project that began this summer. In that pilot, wastewater was collected from five locations across Maryland and analyzed for the coronavirus. The pilot showed that monitoring could produce meaningful results under proper sampling methodology. In most cases, the wastewater sampling results aligned with results observed through clinical testing.

Perhaps most importantly, the pilot project showed that wastewater sampling provided advanced notice of an outbreak before they were seen through traditional testing. Under the Sewer Sentinel Initiative, sampling results that show an increase of infections in congregant living settings will support an active state and local response to limit the spread of the disease. 

Monitoring can help communities know that their homes are safe. If the virus is detected in large quantities it may signal that one or more people are infected. With support from MDH and local health departments, access to testing can identify those with the virus who can take steps to protect themselves and others. Even asymptomatic carriers can be detected with wastewater sampling. 

Wastewater sampling under the new phase of Maryland’s COVID-19 Sewer Sentinel Initiative is expected to begin within a month. More information on Maryland’s response to the COVID-19 emergency is available at

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