What is the minimum length of pup piece to be used in under ground water piping?

The minimum length of a pup piece used in underground water piping typically depends on the specific application and the requirements of the piping system. However, a common minimum length is around 12 inches (30 cm) to ensure proper connection and support between fittings and piping. It's important to follow local codes and standards, as they may dictate specific requirements for installation. Always consult relevant guidelines or a professional for precise specifications.