Abstract: A gauge is disclosed which is particularly suitable for use on stand-alone liquid storage tanks typically found outdoors or on worksites. Fluid from the lower portion of the tank is allowed to flow into a chamber bounded on one side by a resilient deformable diaphragm. The pressure exerted by the fluid deforms the diaphragm displacing it outward, which displacement is mechanically transmitted to cause pivotal displacement of an indicator needle. The amount of displacement of the needle depends upon the magnitude of the fluid pressure, which itself is proportional to the depth of the liquid in the tank, thus providing a reading of that depth.