A senior manager at Severn Trent is urging people to use less water as supplies are threatened by the driest winter and spring in 80 years.
Reservoir levels across the company's region are about 10% lower than they would normally be at this time of year.
Fraser Pithie, Senior Operations Manager, said there needs to be a change in attitude about usage.
He said the firm plans to reduce its leakage levels which currently reach between 23% and 25%.
Customers in north Staffordshire have already been switched to another water supply to conserve levels in Tittesworth Reservoir which is about half full.
Last month the firm said it was not planning to introduce a hosepipe ban but it urged customers not to use them.
Mr Pithie told BBC News that householders need to appreciate how precious water is.
"I accept people pay for it and they might say 'I pay for for my water, I'll use it how I want' but, there's more to it than that," he said.
"We've each one of us got to change how much of this stuff we're using and that only means one thing, we've got to use less of it."
He said stopping leakage is expensive but accepted that levels reaching 25% could be seen by the public and customers as an "awful lot of water".
"But there does come a point when it becomes more expensive to pursue leakage than to supply water."