Auckland is expecting a temperature high of 28C today and Friday - and a 27C high the rest of the week - according to the MetService.
Watercare spokeswoman Roseline Klein said: "Almost all of our water treatment plants are working at maximum capacity 24/7 in order to treat and distribute water at a faster rate than it's being used.
"This is challenging to sustain day after day."
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Klein said Watercare had changed the way it operated its treated water storage reservoirs to make sure there is more water stored in local suburbs in case of an unplanned outage at a treatment plant - for example, in a power outage.
"Water is precious, especially in a drought," she said.
"We all need to use it wisely so that we can reduce the likelihood of formal restrictions should the dry weather continue."
RAIN MADE NO DIFFERENCE
The rain that fell over the city over the weekend made little to no difference to Auckland's total water storage.
As of today, the city's total water storage stands at 65 per cent. On Saturday, 35mm fell in the southern catchment in the Hunua Ranges, south of Auckland, and 14.5mm of rain fell in the Waitakere Ranges, west of the city.
"While we welcomed the rain last weekend, it wasn't enough to end the drought," Klein said.
"In reality, the uplift in our water storage level only lasted 18 hours because of the rate that people are using water."