A boozed-up man and woman plunged from a Brooklyn roof Sunday as they were trying to climb up a water tower on the building, police sources said.

The pair was partying atop the four-story building on Troutman Street near Cypress Avenue in Bushwick at around 7:30 a.m. when the incident, a source said.

The 34-year-old man fell four stories to the sidewalk and suffered severe head and body trauma.

The 22-year-old woman fell around 15 feet. Her condition was not known.