A sensor is provided for a fluid system having a tank and a source of pressurized fluid. The sensor has a sensor body enclosing a sensor element that is configured to sense a parameter of the pressurized fluid. The sensor also has a first passageway configured to fluidly communicate the sensor element with the pressurized fluid and a first sealing interface configured to seal the first passageway. The sensor further has a second passageway configured to allow fluid that has leaked past the first sealing interface to drain to the tank.