@ Nick Stene Dip Dig, ...

@ Nick Stene Dip Dig,

Leakage detection is a very vast subject, and is just not confined to the loss attributed in the pumping/distribution/gravity system to convey treated water. An indepth study of material science, terrain, soil parameters, apart from the length of pipeline is to be considered. If multiple piping materials are used, the demarcation with respect to the material used for that particular stretch needs to be critically viewed. There could be unaccounted losses not attributable to the pipeline but internal plumbing at take off points (e-g, a dripping tap, a malfunctioning flush in a toilet, etc). Leakage identification markers come inbuilt with the latest piping materials to pinpoint the spot of leak. The long term effects of corrosion and biofouling that happens even in treated water  long term can not be ignored. By and large the average break rate of different piping materials have been studied by leading water companies like Anglican Water which uses many piping material. It has to be noted that leakage at the jointing of the pipes takes place first than a pipe burst. The study from Anglican water authority indicates that long term average pipe break per 10 Km of a laid pipeline is lesser in the case of Ductile Iron pipe (despite tyton joints) and properly laid polymeric materials like PE. The pressure in the system you are referring to about is the transmission pressure in the pipeline which needs to be designed at the project stage. As a rule of thumb it is persay ideal to design a pipeline considering frictional losses and static head losses. The Piezometric head principle   need to be incorporated to identify use of water transportation using the potential energy during a rising main and use of kinetic energy accumulated from the raising levels to minimize the cost of pumping. Normally it is ideal to ensure that the pumping head is kept below 100 m, and the concept of boosters need to be considered for conveying long distance pipeline. 

Thank you for your intersting question.