Abstract: An automatically calibrating vacuum relief safety valve is disclosed including a valve body having a plurality of inner cavities, wherein a first cavity of said plurality of inner cavities is in constant fluid communication with air external to said valve body and wherein a second cavity of said plurality of cavities is in intermittent fluid communication with said first cavity, at least one air vent opening positioned between said first cavity and said second cavity and operatively engaged to a releasable seal, said releasable seal connected to a piston member, and a check valve in fluid communication with said second cavity and the suction side of a pump.