As mosquito season ramps up local Zika-related anxiety, the city's reporting an uptick in complaints about empty swimming pools that are gathering standing water.

NBC News reports that these so-called 'zombie pools' have garnered about 491 complaints since June 15th of this year—last summer, there were only 226 complaints. Though the mosquito that carries and transmits Zika to humans has not been found in New York, health officials have been urging residents to report stagnant water, since it can serve as a breeding ground for mosquitos.

Per the investigation, the majority of these empty pools have been found on Staten Island, particularly at foreclosed and vacant properties. The health department is unable to fully drain the pools and instead workers treat them with larvicide, a move residents claim is not enough to combat the issue.

"We've seen other municipalities around this region take measures to be able to drain pools," Councilman Joe Borelli told NBC. "It goes back to the notion of, look, the city is giving you a license, a permit to build your pool. With that license comes responsibilities, and if you're not able to maintain those, the city should have a right to kind of renege it and take measures in the most extreme cases."

The Washington Post reported earlier this summer that empty swimming pools at foreclosed homes have posed a major problem in the battle against Zika and mosquitos, particularly in states hard-hit by the 2008 housing crisis, like Florida.