Civil Defence says more than 62,000 properties in Christchurch still do not have running water, and 100,000 households are without sewerage.
It says people whose properties appear undamaged and without siltation can use their showers, but this must be done sparingly to conserve water.
Civil Defence says toilets can be also used sparingly if they are functioning properly.
Fresh water is available at all times from 25 schools and 12 pump stations, and by daily tanker deliveries in another 26 locations.
Army engineers are also continuing to use a desalination plant to produce clean water in the New Brighton area, and about 4,000 people have collected water there.
