A method and system of testing for package leaks by a test system is disclosed. The test system includes a vacuum source and a test chamber in which a package is received for testing. A package is placed in the test chamber, and a vacuum is drawn on the test chamber by the vacuum source. A predetermined pressure level in the test system is detected, and based upon the detection of the predetermined pressure level, the test system determines when to stop drawing the vacuum. The test chamber is isolated from the vacuum source based upon the determination, and subsequently the test system detects the presence or absence of a leak in the package based on pressure measurements in the test chamber. A timer may be used to determine the delay in isolating the test chamber from the vacuum source after detection of the predetermined pressure level.