Abstract: The invention relates to a reducing agent tank 1 for holding a liquid reducing agent as a so-called SCR tank. The SCR tank comprises at least one device for deaerating the tank, which device is closed off by means of at least one pressure-compensating element which permits an exchange of gas but which closes off the tank in a pressure-tight manner. The reducing agent tank (1) also comprises at least one deaeration line (5) which communicates with the pressure-compensating element, with the deaeration line (5) being guided at least to a point above the maximum permissible fording level of the tank when the tank is in the installation position. The deaeration line (5) has at least one first downward-sloping line section (5a) which branches into a second rising line section (5b) for deaeration and a third falling line section (5c) for gravity-induced condensate drainage (FIG. 1).