Water restrictions have been rolled out across Christchurch to ensure firefighters have enough water saved.
From Thursday, the use of hoses, sprinklers and garden irrigation systems is permitted only on alternate days.
No water can be used outdoors on any day between 3pm and 9pm.
Several consecutive days of hot weather are forecast for the city, with little rain predicted in the long-term forecast, Christchurch City Council head of three waters and waste Helen Beaumont said.
This is expected to push up demand for water and put the city's water supply network under extreme pressure.