SOUTH PORTLAND – A section of Broadway closed since Thursday night because of a water main break is back open.

The break, in front of 724 Broadway, was the sixth in the city in the past two weeks.

There also was a water main break Thursday night on Hinckley Drive.

The Broadway water main break caused damage to J.P. Thornton’s Bar and Grille and Green Postures Yoga. Both businesses evacuated customers when water began pouring in through the doors and floor drains.

The Portland Water District on Friday launched an investigation into the causes of the breaks and if they are related. Michelle Clements, a spokeswoman for the district, said the investigation will look at unusual levels of water use that could cause pressure fluctuation and acidity levels in soil that cause erosion.

The water district, which serves 11 communities, deals with an average of 100 water main breaks a year, Clements said. There have been 13 breaks so far this year in South Portland.

Broadway reopened at 3:30 p.m.