The invention relates to household products, in particular to a household water storage tank. The tank mainly comprises a tank body, a water inlet pipe, a first water outlet pipe and a second water outlet pipe. A first water outlet is formed in the side face of one end of the tank body, a water inlet and a second water outlet are formed in the side face of the other end of the tank body, and the water inlet pipe, the first water outlet pipe and the second water outlet pipe are connected with the water inlet, the first water outlet and the second water outlet respectively; a first water valve,a second water valve and a third water valve are arranged on the first water outlet pipe, the second water outlet pipe and the water inlet pipe respectively, a buffer device for preventing inflow water from being mixed is arranged at the bottom of the box and comprises a support and a groove, and an L-shaped pipe is connected to the portion, in the tank body, of the water inlet pipe; the tail endof the L-shaped pipe points to the groove, a cleaning port is formed in the upper portion of the tank body, and a sewage discharge port is formed in the lower portion of the tank body; a plastic coverand an iron cover are arranged at the cleaning port and the sewage discharge port respectively, a filter screen is arranged at the first water outlet, the second water outlet pipe is connected into atoilet water inlet pipe, and the tank body is a cylindrical tank body.