Wellington Regional Council wants residents to cut down their water use by 10% as supplies fall to unprecedented levels.
The council says at the current rate of usage the region has just 20 days of water left before going into emergency water supplies.
It is using emergency measures to take extra water from the Hutt River, which is running at 25% of its normal flow.
The council's water supply committee chair Nigel Wilson says it plans to introduce a total ban on outdoor water use if there is no rain before the weekend.
