It helps alert them when an outbreak is on its way.
"The wastewater predicts what's about to happen about two to four weeks ahead of time," Chief Medical Officer for the City of Houston Dr. David Persse said during a news conference on Wednesday.
On Wednesday, Houston health officials said the level of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) was 320% higher than the benchmark level set on July 6, 2020.
The Houston Health Department said it's an indication that the virus is rapidly spreading and the increase in COVID-19 cases will likely continue. Persse said the wastewater numbers are "extremely reliable."
"The virus in our community is spreading rapidly. It's spreading everywhere. It's spreading very intensely. And we are at a level of virus in the wastewater that we have never seen before," Persse said.
How do they test the wastewater?
The bottles of wastewater are delivered to a lab at Rice University where it is concentrated, filtered, then genomic material is extracted. It’s also analyzed by the Baylor College of Medicine. Wastewater testing has been used in other parts of the world for disease monitoring and illicit drug use. However, the COVID-19 pandemic is the first time the technique has been used in Houston.
Officials said wastewater testing is the best indicator of the spread of COVID-19 in Houston. It’s because when someone’s sick, they shed the virus when they go to the restroom.