The automatic switch adopts electronics theory, controlled by water current. The pump boosts pressure automatically when the tap is on, and turned off when the tap is off. It is used conveniently, and also saves power. Its copper pump body, copper impeller and stainless steel shaft are corrosion-resistant, stainless. The whole pump is sealed well and the conveyed water will be sanitary. Its total suction lift is high. Flow rate is large. It starts well, switches sensitively and automatically, produces low noise. It also is designed to be low temperature, small volumn, delicate appereance and long-working time.