As Leppington transforms from a rural hub into a bustling residential and commercial centre, the demand on our water infrastructure has never been higher. With new developments like Leppington Town Centre and the surrounding industrial estates, maintaining water safety is critical. One of the most important—and often overlooked—safeguards is the Backflow Prevention Device (BPD) . What is a Backflow Prevention Device? A backflow prevention device is a mechanical valve installed on your plumbing system. Its sole job is to ensure that water flows in only one direction : from the Sydney Water mains into your property.