The road opened back up on Kneeland Street in downtown Boston after a Wednesday morning water main break.
Road crews were out in the heavy rain near South Station had excavated the site of the problem and were still making repairs to the 24-inch main as the downpour started to let up in the early afternoon.
The cause for the break was still unknown, and crews would likely get a better sense of what caused the failure after they had a chance to pull it out and inspect it, a Water and Sewer Commission spokeswoman told Metro.
"What we focus on first is really getting the repair done," said Jeanne Richardson, commission communications director.
Richardson said the goal was to be done with work at the site by the end of the day.
The break, reported around 5:45 a.m. at Kneeland Street between Atlantic Avenue and South Street, blocked traffic downtown, particularly coming off the expressway, which made an already soggy and slow commute that much worse for drivers in the area.