An average 22 per cent of supplies was lost through leaky pipes and mains, pushing up customers' bills and costing the privatised water companies millions of pounds.
The biggest waster was North West Water, where 36 per cent was lost. The Bristol, and Bournemouth and West Hampshire companies lost the least with 6 per cent each, according to Ofwat.
The water watchdog said an additional 1 per cent used by the water companies themselves was included in the figures, making a total of 23 per cent lost, or nearly 842 million gallons (3,828 million litres) a day.
The Cost of Water Delivered to Customers 1991-92 outlined for the first time how much people in England and Wales pay for their water. Ofwat found a wide variation in cost, the average being 50p per 1,000 litres (220 gallons).
Customers in the South-east paid 86p and those in Tendring, Essex, 82p, but those in Portsmouth paid just 33p and Bournemouth and West Hampshire 36p.Reuse content