Washington state has recorded the second-highest level of Covid-19 activity in the United States, according to the latest wastewater data from the Centers for Disease Control and Prevention, with only Texas reporting higher levels.
The figures, highlighted in a report published on Monday October 5, indicate increased levels of SARS-CoV-2 in wastewater across Washington. Such monitoring can identify rising transmission in communities, including infections that may not be detected through clinical testing.
The CDC’s National Wastewater Surveillance System tracks samples collected from treatment plants across the country and uses them to estimate viral activity at state and regional level. The agency says higher wastewater readings may indicate a greater risk of infection in the surrounding population.
However, the data is preliminary and can change as additional samples are received and reviewed. The CDC updates its wastewater information each Friday.
Washington’s Department of Health also tracks Covid-19, influenza and respiratory syncytial virus through its respiratory illness dashboard. The department said the CDC changed its method for calculating wastewater viral activity levels in August 2026, while Washington’s dashboard was still using the previous method as of its latest update on September 30.
