"It is critical we manage demand and give the reservoirs time to replenish. We need everyone to do their bit to cut back on the water they are using because if consumption keeps rising, we will be using water faster than we can fill the reservoirs or move it through the pipes.''
At the weekend Christchurch used more than half a billion litres of water, which is the most water used over a weekend since January 2009.
On Monday the city used 254 million litres in total – the equivalent of 678 litres for every person in the city.
Mr Mackie said long term the council could put in bigger pipes and build more pump stations and reservoirs to enhance the performance of the water supply network over the summer peak but it would cost lots of money.
"We have to look at the considerable impact on rates that would have compared with asking people to conserve water during the hottest period of the summer,'' he said.
One easy thing people could do to ease demand on the network was to cut back on watering their lawn and garden.
"If everyone only watered their garden every second day and only after 9pm or before 6am it would significantly ease pressure on the network,'' Mr Mackie said.
Check out other water saving tips.