About a quarter of Christchurch households still do not have a working toilet, mainly because of silt blocking sewer pipes.
Some 60% of primary waste water treatment plants are working but none of the secondary plants.
Christchurch City Council's water and waste manager Mike Bourke says 18 large suction tankers will arrive from Australia this week to help in the process of removing the silt.
Mr Bourke says it will allow more sewers to be cleared more quickly with the aim of restoring services to households and reducing the volume of waste water flowing into the rivers.
