Pukerua Bay residents could have been drinking water possibly contaminated by sewage for a few hours, Wellington Water says.
This morning a contractor broke a wastewater and water main, potentially contaminating the water for 50 homes in the seaside community north of Wellington.
The water was shut off immediately, but some remained in pipes for people to drink, Network & Customer Operations group manager Gary O'Meara said.
Residents living in Pukerua Beach and Ocean Parade Roads, and Brendan Beach, were told this afternoon not to use water at all.
Wellington Water would supply bottled water, with a tanker coming this evening.
Mr O'Meara said the problem should be fixed by tomorrow morning, but residents would need to boil water for another three days.
A welfare centre had been set up at Pukerua Bay for anyone needing more information, or help finding temporary accommodation.
About 1900 people live in Pukerua Bay.