Abstract: A housing assembly includes a housing, a push button, and a sealing member. The housing includes a bottom plate and a sidewall protruding from the bottom plate. The sidewall defines an opening therethrough and includes a protruding tab protruding from an inner side thereof and extending around the opening. The push button includes a button body extending through the opening and a pushing portion protruding from an inner side of the button body. The sealing member is made of elastic material and includes a first surface and an opposite, second surface. The first surface defines a receiving groove, and the protruding tab is tightly fit in the receiving groove. When the push button is pressed, the pushing portion pushes the sealing member and the sealing member is elastically deformed, thereby preventing liquid from entering the housing through a gap between the push button and the housing.