Dear Nick. You are unable ...

Dear Nick.

You are unable to find such results as it is very hard to generally speak in that matter. You can estimate possible leakages using common methods like FAVAD or using emitter coefficients in hydraulic modelling software. But still, I can give you few examples:

1. WS system in my region has around 10% of water loss in 8 km of mains. Pipe material is cast iron, 30 years old, internal diameter of 600 mm, pressure of 6 bars. Total yearly flow of 15.000.000 m3

2. WS system I recently analysed has around 6 km of main distribution pipe with under 1% of losses. It is new ductile pipe, 400 mm diameter with 7 bars pressure. Total flow around 7.000.000 m3

So you can see that it varies based on pipe material, pressure, construction quality, etc. There are always good examples how to impact on it like working with minimal required pressure by filling a water tank and then continue distribution from that point rather then direct supply to customers. There are many ways for impacting it and from professional point of view, the best way is to consult an expert to make you option analysis with hydraulic model.

good luck...