I need some advice on how to detect an underground water leak / illegal branch.
As background I am the President of a Spanish water community serving about 30 rural properties distributed over several square kilometres. We pump water from a lower deposit to a higher deposit that then feeds the properties, with the height / gravity of the higher deposit providing the water pressure. The upward pipe is PVC 90mm and is buried underground, often under concrete and running through private land. The pipe is about 2 km long. The pumping operation is not continuous and only runs when the higher deposit reaches a minimum level. There are not meant to be any branches off this main upward pipe with all supplies to individual properties run off of a separate downward pipe network.
Every time water is pumped up 20% does not arrive at the higher deposit. During the summer this will run to hundreds of cubic metres of water over a three month period. I have used a local company to try and locate the problem and they have been unable to do so. They have tried pressure testing and seem to have dug a number of holes.
We suspect one particular local farmer has illegally branched in but where the upward pipe crosses his land he has concreted over and will not give access. Using the police to gain access is not an option. As an added complication most properties have their own water deposits for security of supply and so any theft is difficult to spot as it flows into private deposits.
The leak / illegal branch could of course be elsewhere and there may be more than one. The local company seems to have run out of ideas and more importantly a desire to solve the problem.
I have looked into simply laying a new pipe but it will cost several thousand Euros due to the length and terrain.
Can anyone offer any suggestions?
As background I am the President of a Spanish water community serving about 30 rural properties distributed over several square kilometres. We pump water from a lower deposit to a higher deposit that then feeds the properties, with the height / gravity of the higher deposit providing the water pressure. The upward pipe is PVC 90mm and is buried underground, often under concrete and running through private land. The pipe is about 2 km long. The pumping operation is not continuous and only runs when the higher deposit reaches a minimum level. There are not meant to be any branches off this main upward pipe with all supplies to individual properties run off of a separate downward pipe network.
Every time water is pumped up 20% does not arrive at the higher deposit. During the summer this will run to hundreds of cubic metres of water over a three month period. I have used a local company to try and locate the problem and they have been unable to do so. They have tried pressure testing and seem to have dug a number of holes.
We suspect one particular local farmer has illegally branched in but where the upward pipe crosses his land he has concreted over and will not give access. Using the police to gain access is not an option. As an added complication most properties have their own water deposits for security of supply and so any theft is difficult to spot as it flows into private deposits.
The leak / illegal branch could of course be elsewhere and there may be more than one. The local company seems to have run out of ideas and more importantly a desire to solve the problem.
I have looked into simply laying a new pipe but it will cost several thousand Euros due to the length and terrain.
Can anyone offer any suggestions?