Leak prevention fill valve control system for toilet tank

A mechanical water flow measuring and regulating system for preventing loss of water due to toilet malfunctions, the system comprising:

• a mechanical water flow measuring and regulating device communicating with a water fill pipe for a toilet and a water fill valve to start and stop the flow of water through the water fill pipe into a fill tank of the toilet, the mechanical water flow measuring and regulating device comprising a water wheel in contact with the moving water in the water fill pipe and at least one control gear mechanically turned by the water wheel, a regulator arm mechanically linked between the at least one control gear and the water fill valve to control the water fill valve, the water wheel and the at least one control gear structured to measure the quantity of water flowing through the water fill pipe so that after a measured amount of water sufficient to fill the toilet tank is detected as having flowed through the water fill pipe, the combination water flow measuring and regulating device causes the water fill valve to stop the flow of water into the fill tank to prevent a loss of water due to a toilet malfunction.