Residents on Banks Peninsula are being urged to conserve water for the second time this week, due to the cold weather forecast for the next three days.
Fresh drinking water was delivered by tanker to rural communities in Canterbury this week after the water supply was contaminated by the heavy rain.
Christchurch City Council is asking residents in Akaroa harbor, Pigeon Bay and Little River to conserve water as some of the reserves are reaching critically low levels.
Water and Waste Unit manager Tim Joyce said the prolonged bad weather is making the supply of water, clean enough to treat from flooded streams, difficult.
Snow is expected at sea level on the east coast on Wednesday night and Thursday morning, with blizzards in places.