Method for mounting a capacitive level sensor inside a liquid tank having a bottom wall, the sensor having a foot and a measuring portion comprising at least one capacitive element supported by a rigid support extending from said foot, wherein the foot is fixedly secured to the bottom wall of the tank through a retainer, and according to which the rigid support forms an angle with the foot so that the length of the measuring portion of the sensor is higher than the height of the tank in the portion where the foot is located.