Abstract: A pump station flowmeter is disclosed including a pump status comparator for creating level status without being connected to any level sensors by comparing pump status to a list of association between expected pump status and levels. The wet well dimension, pump status signals, clock signals, level status are recorded in memory before being used as input to a flow calculator which calculates inflow and outflow. A flow rectifier readjusts the inflow and outflow according to a variable proportion of the difference between an average of many outflows and one outflow, and using this difference to readjust a variable tolerance and the variable proportion. This optimizes accuracy according to each specific installation. Abnormal pump operations are confirmed when a predetermined number of possible abnormal pump operations occur in a row are detected by comparing the outflow to the average of many outflows plus or minus the variable tolerance.