After spending months figuring out the best way to collect and analyze New Yorkers’ fecal matter for traces of the coronavirus, the city’s Department of Environmental Protection is finally getting a steady stream of data from its new wastewater testing program. What it reveals so far is... basically what we already know.

At this point, data collected by tracking the virus through the city’s sewers largely serves to confirm the upward trend in COVID-19 transmission demonstrated by the massive volume of individual coronavirus tests that have been administered in recent weeks.

“What we’ve been finding in the last six weeks is that in all five boroughs we’re seeing increases and that pretty much aligns with what the city Health Department has been finding as well,” DEP Commissioner Vincent Sapienza told Gothamist Thursday.

But that doesn’t mean wastewater testing is a wash. The information gleaned from the sewers will likely become vital once people start getting vaccinated against COVID-19 and fewer people are getting individual tests for the virus, Sapienza says.

“Testing sewage may be a much more powerful tool when we get into 2021...and [positive COVID-19] rates are getting closer to zero,” Sapienza said.

For instance, he said, if there were few or no fragments of the virus being detected “and now we’re seeing something in this catchment area, that may allow us to work quickly and react when there may be very little testing going on.”

Wastewater testing has been used in this way to alert governments to the resurgence of other diseases that have been largely eradicated, such as polio. The city is also looking at its potential for tracking the seasonal flu.

Nationally, interest in wastewater testing as a tool for tracking COVID-19 has exploded in recent months and the Centers for Disease Control and Prevention recently announced the creation of a National Wastewater Surveillance System that will collect data from state and local governments. In the scientific community, wastewater testing has been lauded as a method of tracking the virus that is both cost-effective and potentially more equitable and consistent than individual testing efforts, which took a long time to ramp up and are still inadequate in many places. Because the coronavirus can show up in a person’s feces before they show symptoms, wastewater testing also has the potential to catch cases individual tests would miss.

“We all thought this was a really good way of getting a sense of what’s going on as far as spread in the community because, while some people may get tested or may not get tested or be showing symptoms or be asymptomatic, if you have COVID-19, you excrete viral fragments every time you use the toilet,” Sapienza said.

Costs associated with the city’s wastewater testing program have so far been minimal. The city has invested $250,000 in new equipment, brought on 3.5 new staff members (DEP shares staff with academic institutions), and taken advantage of $300,000 in leveraged funding through grants and partnerships with academia, a DEP spokesman said.

Some wastewater testing experts have suggested that New York should be collecting samples from more sites with greater frequency. So far, DEP is collecting samples twice a week from 14 wastewater treatment sites around the city, making the data from wastewater testing less granular than the neighborhood-level rates the city Health Department is able to provide based on individual testing. For now, DEP is looking at a modest expansion, with the goal of collecting samples from 25 or 30 sites around the city in the future, Sapienza says.

In places where it’s been used in a more targeted way, wastewater testing has already demonstrated the ability to help prevent potential COVID-19 outbreaks. For instance, researchers with Arizona State University's Biodesign Institute found traces of coronavirus in the wastewater of one of the ASU dorms as students were moving in this year. That led the school to test everyone who lived or worked in the dorm and find two asymptomatic students who tested positive. Those students were then quarantined, possibly preventing an outbreak.

Dr. Jay Varma, senior health advisor to Mayor Bill de Blasio, told local news outlet The City that there is a possibility New York will use wastewater testing to monitor the coronavirus in “a very defined geographic area” or specific facility in the future.

But for now, individual testing remains the dominant mode of tracking the virus.

“In the city we’re doing so many [individual] tests in all neighborhoods, so we’re seeing our results almost in the same timeline that the city Health Department is,” said Sapienza. “In other municipalities or states where they don’t have literally tens of thousands of tests being done everyday, [wastewater testing] might be a better or quicker tool.”