Crews are working to stop a ruptured main from spilling sewage into the Schuylkill River.
The leak was discovered around noon on Monday at a main off Route 10 and Brentwood Drive in southwest Reading.
A significant amount of sewage has already spilled from the 42-inch main into the river, said Charlie Jones, the director of public works.
Jones said crews will be working around the clock to stop the spill.
The break in the main could be the result of the recent earthquake, the hurricane or just old age.
This is the same main that ruptured and resulted in a major sewage spill back in 2008, officials said.