The Water Supplies Department says fresh water is gradually being restored to affected areas of Tuen Mun from 6:30am.
Overnight, thousands of residents in north Tuen Mun saw their supplies cut off, as authorities rushed to complete emergency works to fix a burst water main on Tuen Mun Road.
In a post on its Facebook page, the Water Supplies Department said an engineering team had worked overnight, fixing the water main at around 3am.
It thanked the public and road users for their understanding.
It also said it was grateful to the Home Affairs Department for coordinating with district councillors and care teams in the area.
Earlier, the New Territories West Cluster of the Hospital Authority said water wagons were sent to Tuen Mun, Castle Peak and Siu Lam hospitals, while services there weren't affected.
Road repair work has also been carried out the affected lanes were reopened at about 6am.