Jules Radich said the slip in Maia on Friday morning had affected a 500m section of the water main serving all West Harbour suburbs.
"The pipe that is affected is well buried under the slip . . . it's quite significant what needs to take place (to fix the pipe), it's problematic actually."
And any fix, temporary or otherwise, cannot be made until it is known if the slip is stable.
A DCC spokesperson said they hoped to have a temporary solution in place on Sunday.
"In regards a timeframe for a permanent solution, that will depend on further assessments.
"However, we hope to have partial reconnection completed tomorrow. This would involve reconnecting to the St Leonard’s reservoir," the spokesperson said.
Residents are thought to have about two days water remaining, based on current usage, so are reminded to conserve water as much as possible.
A boil water notice has been issued for all DCC-supplied properties in West Harbour from District Rd in Roseneath to Lewis St in Deborah Bay.
"This is a precautionary measure as we have switched to a new water supply following damage to the water main in Maia," a council spokesperson said.
The boil water notice will remain in place until water quality testing of the new supply is complete.
The Maia slip was the most significant issue in terms of the city's recovery following the downpour of the past several days, he said.
"It's also blocking the (road to Port Chalmers), which is a busy road."
"Maia is a much bigger problem."
Contractors are hand digging a trench around the large slip to get water reconnected to West Harbour communities.
"It's just like the old days," said Dunedin City Council three waters capital delivery team leader William Clifford at the site today.
There was not any access for machinery in some parts of the area around the slip, he said.
Residents in the West Harbour area, apart from St Leonards, were receiving water from a local reservoir in the meantime.
The contractors were working to install a temporary pipe-line up the side and around the back of the slip on advice from geotechnical engineers to avoid the slip as much as possible, Mr Clifford said.
West Harbour community board member Jarrod Hodson said he had been to have a look and the slip was "massive".
"It's actually quite scary."
The community board was working hard to inform the community through its Facebook community pages.
They had been in touch with the three or four families affected by the slip, which was as many as knew there were at Saturday morning.
The house in the path of the slip was very large and he could not see how those people would be getting back into it.
One lane of SH88 around the edge of the harbour had been reopened for residents and emergency vehicle access only.
Water tankers were able to get into the area for drinking and cooking water supplies.
People could also get to and from Dunedin and Port Chalmers via Upper Junction Rd, though the route is not suitable for heavy vehicles.
Homes near the slip were evacuated on Friday morning, and more had been evacuated since.
Most of the 25 people still in a welfare centre set up by the council last night were from the Maia area, he said.
He did know how many properties were evacuated or how many properties were affected by the slip.
A DCC staff member had a lucky escape after they went to investigate reports of damage to the water main.
A DCC spokesperson said the staff member's vehicle got stuck in the mud, so they parked and were picked up by a colleague.
The slip then gave way, sending torrents of mud - and a DCC ute - down the hillside.
The staff member was well clear of the area when the slip struck, the spokesperson said.
