The Water Supplies Department said water supply will be suspended in parts of Tuen Mun from 11pm on Tuesday, due to emergency repair works following a burst water main on Tuen Mun Road.
Officials said there will be no water supply in several areas, such as the northern parts of Tuen Mun; north of Wong Chu Road; south of the junction of Tsun Wen Road and Tsing Chung Koon Road; and northwest of Tuen Mun River.
The department said some buildings have water tanks, so supply can still be maintained for a period of time.
The authorities said workers are working on emergency repairs in order to restore fresh water supply by early Wednesday morning.
They also hope to reopen Tuen Mun Road by the morning rush hour.
The New Territories West Cluster of the Hospital Authority said there are water wagons to support the three hospitals in the affected area, namely Tuen Mun Hospital, Castle Peak Hospital and Siu Lam Hospital.
The authority said services at the three hospitals are not being affected for the time being.