The city couldn't quickly repair a water main break that flooded a portion of the Two Bridges area in the Lower East Side Monday because the main's valve was located under an active construction site, city officials said.

The flooding inundated a stretch of South Street near the FDR Drive, with photos and video from the scene showing parked vehicles immersed in floodwater.

The portion of South Street from Robert Wagner Place to Catherine Slip remained closed Tuesday morning as the city's Department of Environmental Protection worked to repair the 30-inch-diameter main installed in 1952. Water mains are the primary subterranean arteries that deliver water to smaller pipes connected to buildings.

"There's a construction site right here under South Street under the underpass to the FDR Drive and it made it difficult for us to get to that valve," DEP Commissioner Vincent Sapienza told reporters at the scene Monday.

While water service was not interrupted during the main break, residents reported brown water coming out of faucets in nearby buildings and flooded-out vehicle engines.

DEP spokesman Edward Timbers said in an emailed statement that "a disruption to the water delivery system, such as the use of a fire hydrant, construction or a water main break can cause the water to become temporarily discolored. Discolored water is not harmful, but residents should run their tap until the water runs clear and cold."

The FDNY said they were on scene from about 4:45 p.m. to 9 p.m. Monday night to control the flooding.

This is at least the fourth major Manhattan water main break in 2020: in mid-January, a water main broke on Broadway just north of Columbus Circle, creating a lagoon outside of Lincoln Center. Another water main break happened a week later on Central Park West between West 102nd and 103rd Streets. Last week a water main break caused flooding in Morningside Heights.

Sapienza said at the press conference "there are 6,800 miles of water mains now and breaks do happen. New York City actually does a terrific job in keeping the number of water main breaks to a minimum. We're much lower than the national average."

According to the DEP spokesman Timbers, the "industry goal is 15 water main breaks per 100 miles of main. National average is 25. In NYC we average 6.6 breaks per 100 miles of main."

The DEP recorded 428 water main breaks in 2017, 521 in 2018 and 459 in 2019 -- and that so far this year to date the city has seen a ten percent decrease in breaks compared to the same time period of 2019.