Abstract: Examples of calculating a minimum pipe wall to determine a pipe wall failure probability are disclosed. In one example implementation according to aspects of the present disclosure, a first acoustical sensor is connected to a pipe a distance from a second acoustical sensor connected to the pipe. A computing system is communicatively coupleable to the first and second acoustical sensors. The computing system calculates an average maximum pit depth value of a plurality of pits in an outer surface of a pipe wall of the pipe from a known initial pipe wall thickness value and an average present pipe wall thickness value. The computing system also calculates a minimum present pipe wall thickness by applying a statistical technique to the calculated average maximum pit depth value. The computing system determines a pipe wall failure probability based at least in part on the minimum present pipe wall thickness value.