A massive water main break in Philadelphia sent tens of thousands of gallons of water rushing through the streets in Center City, causing power outages, road closures and bus detours during the Tuesday morning commute.

The 48-inch main reportedly broke around 4 a.m. just blocks away from City Hall. It was not immediately clear what caused the incident, but two hours later, water was still gushing through the area.

“This is the worst water main break I’ve ever seen,” a Philadelphia Water Department spokesperson told FOX29.

SEPTA, Philadelphia’s transportation authority, said at least six bus lines were diverted Tuesday because of the flooding.

The PECO energy company told NBC 10 that more than 1,000 customers were without power. Businesses also reported water seeping into their basements, according to ABC6.