The girl was among visitors to a Snow Drive home when she drifted into the deep end, responders said.
The others apparently didn't know how to swim and, instead, tried to get her to grab onto items so they could pull her out, they said.
Police instantly got to the home, on a private road off a dead end, and furiously tried to revive the victim before she was rushed to the hospital.
The prognosis wasn't good given how long she's been under, they said.
Mahwah a month ago had two drownings within days of one another.
A resident in the Rio Vista development was found dead late last month in what her husband told responders was a tragic accident.
SEE: Mahwah Woman, 55, Drowns In Backyard Pool
Less than a week later, a Bergenfield man drowned at the Ramapo Reservation.
SEE: Bergenfield Man, 57, Drowns At Ramapo Reservation In Mahwah
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