Apparatuses and methods are provided for detecting contaminant in a fuel system, such as a fuel system of an internal combustion engine. The apparatus includes a fuel filter comprising an upper unit having a fuel inlet port, a fuel outlet port, and a closeable vent port and a lower unit releasably mounted to the upper unit and comprising a contaminant collection zone adapted for holding collected contaminant and a closable contaminant outlet port adapted for draining the collected contaminant. The apparatus further includes a programmable low-voltage variable contaminant detection sensor formed integrally within the upper unit of the fuel filter and comprising detection probes extending into the lower unit of the fuel filter for sensing contaminant levels within the contaminant collection zone, the sensor being adapted for generating a signal upon detection of a predetermined level of contaminant in the contaminant collection zone. The apparatus further includes at least one indicator for producing an alarm condition in response to receiving the signal from the contaminant detection sensor.