Heater and water dispenser

The heater comprises a shell assembly, a water passing plate assembly, a heating assembly and a heat storage part, the water passing plate assembly, the heating assembly and the heat storage part are arranged in a heating cavity formed by the shell assembly, the water passing plate assembly comprises a first water passing plate, a second water passing plate, a water inlet pipe and a water outlet pipe, and the first water passing plate and the second water passing plate are attached to each other; a water channel groove is formed in the first water passing plate and/or the second water passing plate and used for forming a first water channel between the first water passing plate and the second water passing plate, one end of the first water channel communicates with a water inlet pipe, and the other end communicates with a water outlet pipe; the heating assembly is used for heating liquid in the first water channel; the heat storage part is at least arranged between the water passing plate assembly and the hea