The invention relates to a device (10) for dispensing a liquid in a tank, that comprises an elastomer member (16) that can assume a liquid release position for letting the liquid out of the device, and a check position for preventing the liquid from flowing back inside the device, wherein the device further comprises means (27, 36, 38) bearing on the elastomer member (26) at the level of a recessed area (31, 40) and ensuring the deformation of the elastomer member in the check position.
