A landslip caused by heavy rain that battered the region this week ruptured the water main, which could take several days to repair.
The Wairoa District Council had notified the Ministry of Education schools, kindergartens and early childcare centres in the town would need to close because of the problem, Hawke's Bay Regional Council spokesman Drew Broadley said.
There would also be an impact for people heading back to work on Monday, he said.
Water tankers were being brought in to supply households with water while engineers and contractors continued to work on the pipeline.
Water would be pumped into the town supply periodically tomorrow for residents to replenish household water stores and carry out general household tasks.
This would be rationed to no more than 20 litres per person.
The council asked residents to continue to conserve water, avoid unnecessary washing and laundry, and consider their home water storage options.
Residents also needed to switch off hot water cylinders to avoid burning out the element of the heater when dry. Portaloos had been placed outside public toilets for general use.
Civil Defence on Thursday declared a state of emergency for the region after extreme weather forced the evacuation of more than 100 people from 14 coastal communities.
Yesterday, up to five children were evacuated by helicopter from Aramoana and eight people by four-wheel drive from Mangakuri.
It was expected to take up to three weeks to reopen access to Aramoana, and access to the southern end of Pourerere Beach was closed indefinitely, Central Hawke's Bay Civil Defence local controller Te Aroha Cook said.
