A window washer fell to his death from an Upper East Side town house Monday afternoon, police said.

Paul Benalcazar, 57, was working at 115 E. 81st St. at around noon when he fell from the second floor, police sources said.

“He and his wife have a company washing windows,” said Ed Stern, the building’s owner for more than 20 years. “I have a home office. I heard a commotion and I followed it up. [Witnesses] were saying, ‘He’s dead. He’s dead.’

“It’s just a tragic accident and very upsetting,” said Stern, who says he called 911. “It shows you how precious life is.”