Answered by Bruce Horton

Question Details:  What is the economic level of leakage? How is it measured?

This is the point from which reducing leakage actually costs more than developing new water resources from other sources. See http://www.ofwat.gov.uk/aptrix/ofwat/publish.nsf/Content/WaterResLeakage for some FAQs on leakage - also see Water UK statement on leakage.