A tank for storing an internal combustion engine exhaust gas liquid additive, the tank including a wall defining an internal volume, an electrical component located in the internal volume, and at least one electric cable configured to connect the electrical component to a voltage source outside the tank, at least one portion of the electric cable being inserted into an intermediate part connected to a base plate mounted over an opening in the wall, the base plate incorporating a casing mounted leaktight around an orifice in the base plate. The intermediate part is fastened by a quick-connect coupling including an electrical connector to which the electric cable is connected leaktight with aid of a seal and that emerges from the orifice in the base plate to outside the tank. The seal is inserted between the intermediate part and the connector and/or into a housing of the intermediate part.