Blue Water Baltimore's waterkeeper team is on the scene at a plume that's spreading into the Inner Harbor via Canton Waterfront Park.
The city's Department of Public Works said later that the problem was caused by a 6-inch water main break.
"Early this afternoon, DPW identified a 6-inch water main break at 932 S. Robinson St. In addition to the discolored water in the Harbor, the broken water main caused 100 water service outages," said Acting Director Matthew W. Garbark.
"DPW’s Utility Maintenance Division is on site making the necessary repairs."