Active faults mechanism impacts on water resources in different way and creates many natural and geological phenomenon"s that. This cases is called A, and active faults finding is possible by determination of natural and geological phenomenon that created by its influences on water resources. This cases, is called B and Process of A and B suggested reversible reaction , that means where evidence and data is less for active faults distinguishing, it may be use the residue of its effect on water resources (natural and geological phenomenon of water resources) for active faults type and it"s mechanism determination. This research aim is inspection of the faults that influences water resources in the Lar region in northeast of Tehran, Capital of Iran.