The break happened near the intersection of Washington and Kneeland streets near Tufts Medical Center just before 6 a.m., authorities said. Lagrange Street also flooded.
It's the same area where crews were conducting leak inspections on Thursday afternoon, Boston Sewer and Water Commission tweeted. Officials said they shut off the line at 8 a.m. Friday to make repairs.
The force from the 12-inch pipe rupture caused the sidewalk to buckle near 660 Washington Street, and crews were on the scene Friday morning cleaning up the area.
Officials said drivers should expect heavy delays in the area while workers remain on the scene.
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