This 4 inch lead free reduced pressure zone assembly with its exclusive design incorporating the air-in and water-out principle for protection during an emergency condition prevents the flow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as health hazards and from other contaminants found at the service line entrance. This assembly consists of a lead free body, non-rising stem resilient seated gate valves, captured spring check valves, replaceable seats, top mounted test cocks, and a field reversible pressure differential relief valve.