Abstract: The present invention is a cap tester for a water resistant cap for medical video equipment that comprises a neck capable of insertion within the cap. The neck has an air duct extending therethrough. Preferably, the neck further comprises at least one projection extending outwardly from the neck. The projection mates with interior grooves of the cap to releasably connect the cap tester to the cap. A collar extends outwardly beyond the neck to provide a cover to the neck upon insertion into the cap. A conduit extends above the collar and substantially aligns with the duct within the neck that may be connected to a positive air supply. Thus, upon placing a cap tester within the cap, the method of the present invention comprises pressurizing the cap and cap tester, submersing the cap and cap tester in liquid and observing the immersed cap and cap tester for air bubbles thereby indicating a leak in either the cap frame or any seal located therein.