Authorities said the break was due to a construction project near the Peter Egnor Bridge on Albany Avenue.
Contractors were trying to repair a fender system for boats to go through the bridge. The project required the installation of a 24-inch fiberglass piling. This piling somehow pierced a 36-inch water main under the water.
Residents in the Lower Chelsea area lost water for part of the day but the pressure is slowly returning to normal.
"It's not completely fine, but a little bit coming out, like 80%," said Gerald Spence. "The showers not really coming out that much, so you can't get that shower experience--we'll have to take a doggy bath."
G. Bruce Ward, executive director of the Atlantic City Municipal Utilities Authority, says crews have secured the breach and will assess the damage to begin structural repairs.
Some residents reported discoloration as service slowly came back, but it's a temporary relief until emergency repairs can be done.
"We wanted to make sure that the public knows that this water is safe and it's drinkable, but we are asking folks to restrict the over usage of water," said Atlantic City Mayor Frank Gilliam during a press conference on Wednesday evening.