The partially clothed 33-year-old woman was found in a Soho House room after police received a 911 call from the hotel at about 3 a.m.
Water was discovered leaking from a ceiling and hotel staff went to the floor above to investigate. They found the woman, dressed in a sweater and underwear, submerged in the tub.
There were prescription drugs found at the scene, and the woman had some small marks on her neck, the official said. The official spoke to The Associated Press on condition of anonymity because the official was not authorized to speak publicly about a person not arrested of a crime.
The woman was not immediately identified. The medical examiner's office will determine the cause of death.
Nicholas Brooks, the 24-year-old son of "You Light Up My Life" songwriter Joseph Brooks, was seen leaving the hotel earlier and then returned a few hours after police arrived, said the official. In an unrelated case, the father is fighting charges that accuse him of molesting would-be actresses in his Manhattan apartment.
The younger Brooks has not been charged, and it wasn't clear if he had an attorney.
The Soho House is located on Manhattan's West side in a neighborhood frequented by stars and the city's elite, near chic restaurants like Spice Market and Pastis. Its website says it has 24 rooms that offer guests "a unique combination of luxury and style." It says card-carrying members have to be verified at the front desk. The building has a screening room, library, heated rooftop pool and fine dining.
On Thursday afternoon, the street was quiet as a few crime scene investigators went in and out of the building. Holiday shoppers milled nearby at upscale boutiques glittering with red and green tinsel.
The elder Brooks, 72, has been accused of raping 11 women he lured to his apartment with the promise of a starring role in a movie. He has pleaded not guilty to sexual assault charges and is free on bail. His next court date is Dec. 21.
He won the Oscar for Best Original Song for the 1977 ballad "You Light Up My Life." He also wrote and directed the movie "You Light Up My Life," about a comedian who has a one-night stand with a director.
The father's attorney had no comment Thursday.