Christchurch City Council says it hopes to get water back on in Lyttelton on Friday.
The town has been badly damaged, with 60% of buildings in the main street damaged by Tuesday's 6.3-magnitude earthquake.
The council's water and waste manager, Mark Christison, says reticulated water has been restored to about half of Christchurch, but not at full pressure.
Mr Christison says the water is mainly out to the eastern part of the city and the Lyttelton basin, but these areas are being served by water tankers.
He says pumping stations near the Port Hills were restarted on Thursday, and it should be possible to get water over to the port area in the next 24 hours.
Lyttelton Tunnel to reopen
The Lyttelton Tunnel will be reopened to all traffic by Saturday afternoon.
The tunnel was closed immediately after the quake when rockfalls caused significant damage to the tunnel canopy and control building.
The tunnel was opened to emergency vehicles on Tuesday afternoon and Transport Agency workers are trying to remove the risk of further rockfalls.
Meanwhile, the port at Lyttelton is expected to reopen on Saturday.
Oil tankers and cargo ships carrying water and emergency vehicles will be the first to unload and services should be back to normal by Monday.