Hey there I am Laura Avila Barraza Working as a powerhouse electrician.
Water has a much greater electrical resistance than copper, which means it would cause a large reduction in voltage after long pipes filled with water.
I think this is the main reason,:
Water pipes can leak if broken
If a water plastic pipe breaks, dirt can penetrate, resulting in zero or less good conductivity.
A copper cable always has a certain diameter which is fixed, with water it depends on the pressure of the tube.
The pressure is necessary to keep the water at a pressure that does not leave bubbles.
The water can freeze, which can lead to several conductivity properties.
You need more pipes, if a pipe breaks, the possibility is that the water will "mix", causing a shortcut. A clean cut of copper wire will not directly cause a shortcut.