Households are being urged to turn off lawn sprinklers, not wash their car and take shorter showers amid concerns over a heatwave water shortage.
Anglian Water is calling on people to be aware of how much water they use as the region swelters in soaring temperatures.
It comes as Norfolk fire service warned the hot and dry weather means the risk of wildfires is “extremely high”.
Temperatures were hitting 33C in parts of the region on Monday and could head to 38C by the end of the week.
That will be hotter than Jamaica, the Maldives and the Bahamas, with the hot weather set to ramp up again at the weekend.
The water company says it expects to see peak demand levels skyrocket, putting pressure on the water network.
It is urging people to avoid paddling pools and watering the garden with hoses as well as long showers.
Sarah Castelvecchi, water saving manager at Anglian Water, said, “We want everyone to enjoy the fabulous sunshine and being outdoors, however we would like to ask everyone to think about how they are using their water.
“Paddling pools are the go-to cooler, but a standard pool can use up to 400 litres of water – that's four full water butts. It would be great if people could reuse the water on their gardens, instead of from the tap, as their plants will be hot too.”
The water company provides more than four million customers with drinking water across the region supplying on average a billion litres of water a day from a combination of groundwater sources and surface water reservoirs.
Ms Castelvecchi added: “We’re asking people to use the water they need to stay hydrated and healthy; we want everyone to use water wisely and reuse wherever possible to help us keep taps running this summer.”
One minute less in a shower would save eight litres and turning off a tap a minute early would save six litres, she said.
Hosepipes used 1,000 litres an hour, "so simple things like putting hose away make a massive difference", she added.
The fire service has urged people not to have barbecues on open grass, take extra care stubbing out cigarettes and not leave glass on dry ground as it can start a blaze that could sweep out of control.
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