It happened on 13th Street near University Place sometime around 6 a.m.
The FDNY and water company were able to shut off water to the area around a half-hour later.
13th Street was closed for repairs, and it is unclear when lanes will reopen.
The Department of Environmental Protection said water service has been shut to the impacted area, and crews are on location excavating to determine the source of the leak.
Approximately 150 households and six businesses are affected.
The cause of the water main break is not yet known.
Ex-Brit turned Manhattan resident since 2008.