Which probably isn't that bad in the scheme of things - that's 15 million people. Amazed the 'experts' couldn't field your question.
I've just checked the Yorkshire water leakage figures - just within targets and managed to get a near 300k bonus. A piffling 283 million litres a day. Bravo. Daily *consumption* is 'only' 700Ml/d ffs.
Mind, they picked up 10s of millions in fines for sewage dumping, poor water quality and poor service. But offset a large chunk of the fines with a £17m bonus for a mere 4500 external sewer flooding incidents. Might explain the poor quality of public bathing pool water.