A boil water advisory is in effect for nearly 100,000 Pennsylvania American Water customers in Washington and Allegheny counties following a major water main break in Elrama. According to CBS News, the advisory was issued due to a power surge that depleted water storage at the Aldrich Water Treatment plant, potentially causing contamination through backflow. The break occurred late Friday night, leading to significant flooding and damage, including the trapping of firemen at the Elrama Volunteer Fire Company. Pennsylvania American Water is conducting tests to ensure water safety, with the first round of samples showing no bacterial contamination.