Levels of COVID-19 in wastewater collected from West Davis — which had increased during the last two weeks of April — dropped back down to previous levels last week and officials from Healthy Davis Together say they are still working on how to interpret what it all means.

Since November, wastewater samples have been collected at multiple locations throughout the city’s sewage system and analyzed in a lab at UC Davis. Because the virus that causes COVID-19 can be shed in the stool of infected individuals, monitoring sewage provides an indication of virus levels in different areas of the city, though results are not isolated down to individual households.

In announcing the expanded wastewater monitoring system in late March, Healthy Davis Together said the goal was to provide an early warning system that will alert officials to an increase in virus activity among both symptomatic and asymptomatic individuals and better direct individual testing efforts.