The rupture in the 2300 block of Shelter Island Drive was reported around 9 a.m., according to Arian Collins, spokesman for the city's Public Utilities Department. Crews got the water shut off about 45 minutes later, he said.
Collins said most Shelter Island businesses were without water service while crews were working on repairs.
Some of the businesses affected include Bali Hai, Humphreys, Kona Kai, Best Western Hotel and Fathom restaurant, according to Collins.
Service was estimated to be restored between 5 and 6 p.m.