A water main break on Main Street in South Portland is expected to cause traffic headaches for a second day.

The area around 380 Main St., which is Route 1, will be restricted to one lane after 7 a.m. Thursday and could be closed altogether, South Portland Police Lt. Tom Simonds said.

The busy section of road is near a major intersection with Broadway and the main entrance to the Rigby rail yard and a Hannaford Supermarket distribution warehouse.

“After 7 a.m., please avoid the area,” Simonds said.

Police received the report of a major water main break on Main Street at the intersection with Rumery Road at 1:45 a.m. Wednesday.

Portland Water District crews worked on the break all day, but were unable to fix it, Simonds said.

He said he didn’t know how the break occurred, but police found water bubbling out of the ground on both sides of the road.

During the day Wednesday, police routed traffic away from the area between Cash Corner and Mardale Avenue and were urging drivers to seek alternate routes.

The road was opened to two lanes of traffic Wednesday evening.