Sydneysiders have soaked up more water in one day than they have on any other day in more than a decade after enduring sweltering conditions.

Demand for water on Sunday topped the peak of the past 14 years at 2.215 billion litres with temperatures hovering around 35C in the city and 40C in the west.

That’s about 8.8 billion glasses of water and the highest daily usage since January 29 in 2003 when there was a demand for 2.273 billion litres.

The 54.5 billion litres soaked up in total this January is also 24 per cent higher than last year, according to Sydney Water.

But with temperatures set to cool on Monday demand is expected to ease.