AUSTIN (KXAN) — As more people use at-home tests to determine if they have COVID-19, Austin Public Health says COVID-19 cases in Austin are underreported right now.

Since May 1, APH said they’ve gotten roughly 700 positive COVID-19 test self-reports: there were around 100 in April, 430 in May and there have been 224 so far this month. You can report your COVID-19 test results to APH on their website.

That lack of reporting is one of the reasons the health department has turned to wastewater testing to monitor the pandemic.

“We know case counts are underreported nationwide. At-home rapid tests are readily available and there isn’t a state or federal requirement to collect, track or investigate self-reported tests,” a spokesperson for APH said. “APH epidemiologists consider other disease surveillance indicators in addition to positive lab-confirmed results including wastewater surveillance.”

That latest wastewater testing shows COVID-19 might be spreading in our community again. According to APH, COVID-19 copies in wastewater have gone up roughly 25% from the end of May to the second week of June. The latest COVID-19 wastewater monitor reflects that uptick.

Leaders have said when there is less COVID-19 spread in the community, wastewater can alert officials to changes more quickly than when case numbers are high and there is significant COVID in wastewater.

“The only way to get that two-week advance notice is when the cases are so low you can spot a difference,” Kerry Kinney, a professor in the Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin, said last month.

According to the CDC, most sites around the country are reporting “moderate” COVID-19 levels in wastewater. Around 33% of sites are seeing some of the highest levels of COVID shed in their wastewater since December 2021, the CDC also reported. There are also a handful of stations that are seeing a decline in levels.

UT researchers have said monitoring wastewater will alert health leaders to future rises in cases before they are detected using clinical tests — which will be especially important as people stop testing regularly and resort to at-home tests, which are not always reported to the health department.

The sampling in Travis County is happening at the Walnut Creek Wastewater Treatment Plant and the South Austin Regional Wastewater Treatment Plant. Those samples are sent to BioBot Analytics, which is partnering with the CDC to publish the data for the public.

You can track Travis County’s wastewater testing data in real time here.