Its head of strategic asset planning, Dr Geoff Darch, said its teams were “working 24/7 to keep taps flowing”.
“Understandably, customers have wanted to stay cool and have fun in the sun, but the unrelenting conditions are placing the environment and water supplies under increasing strain,” he said.
“We are now at the point where we need to ask customers to help by hanging up the hosepipe, letting lawns go brown, cars go dirty and using water even more wisely,” he added.
Anglian Water has joined other organisations in a campaign to promote water-saving ideas, external.
He said the company had prepared for periods of prolonged dry weather and invested hundreds of millions each year “to build our region’s resilience”.