A system and method for determining a condition of a filter filtering fuel associated with an engine. Input information relating to the operation of the engine is provided by a plurality of sensors. At least some of the input information is used to determine a plurality of input variables, the plurality of input variables representing a plurality of engine operating conditions including engine run time, engine torque and engine speed. An algorithm incorporating the input variables is used to determine the condition of the filter. Information concerning the condition of the filter may be output to a user such as an operator or service provider.