The 20-inch main broke in the area of Sip Avenue between Bergen and Summit avenues in Jersey City just after midnight, and officials hope to have the problem fixed by the end of the day.
Because the break happened near the Journal Square PATH station and bus terminal, some mass transit delays were possible.
"It appears it's a 20-inch break, which is a significant water line," Emergency Management director Greg Kierce said. "The problem we're having, obviously, it's a major transportation area up here. We're waiting for crews to come in now, and in all probability, it's going to cause significant disruptions in the morning, for the commute."
Luckily, only limited bus and train delays have been reported so far.
"Right now, there hasn't been any issues," Kierce said. "We had a lot of flooding. You know, when you this type of water main, it's a significant pressure and things like that. So we asked Hudson County road department to come in to assist with opening catch basins and things like that."
United Water crews managed to shut off the flow of water just before 5 a.m., but it is expected that Sip Avenue will be closed for much of the day.
Several business and homes were affected with a water outage, but no boil water advisory is in effect for those who still have water.