The hidden water tank can be rearranged through the design of real wall or fake wall to increase the storage space, make the bathroom cleaner and realize the rational use of space. Hidden toilet water tank can be installed in front of solid wall, light brick wall or light steel keel wall, and can also meet the design of wall-mounted toilet on fashion island. The bracket of the hidden toilet water tank provides support for the wall-mounted sanitary ware. Without the shackles of floor-standing toilets, designers can create more modern bathroom space. At the same time, the hidden toilet water tank also has a bracket-free type suitable for the combination of drainage toilets after landing.