Hole-y cow — it’s the mother of all potholes!

A giant pothole — stretching 12 feet long and 5 feet deep — opened smack in the middle of a Bronx street, prompting city officers to rush to the scene Friday, city sources said.

Below the concrete, water from a broken main spurted for more than 90 minutes, filling the hole on West 173rd Street near Amsterdam Avenue, a Department of Environmental Protection source said.

“It really isn’t as bad as it looks,” the DEP officer said.