The Privatised Water supplement distributed recently with NCE was a very interesting read. However, it was marred by one aspect.
You show estimated leakage as a percentage. This is very misleading as an indicator for efficiency of managing water system infrastructure, because it is so strongly influenced by consumption.
With consumption of around 550 litres/service connection/dayin England and Wales, losses are 100l/service conn/day or 15.3% (= 100/650). In German and Japanese cities, with around 2000 litres/service connection day consumption, the same losses of 100 l/service conn/day would be only 4.8% Most countries have significantly higher consumption per connection than UK. By using percentages you unwittingly prejudice what is actually a remarkable success story in the privatised companies.
The International Water Association Task Force on Water Losses has recently recommended that the best simple measure for real losses is Litres/service connection/day when the system is pressurised (to allow for intermittent supply situations).
Allan Lambert (M), firstname.lastname@example.org