This 1 in lead free cast copper silicon alloy N shaped reduced pressure zone assembly is designed to prevent the reverse flow of high hazard (toxic) fluids found in the 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 used in water services to industrial plants, hospitals, morgues, mortuaries and chemical plants and is also used in irrigation systems, boiler feed, water lines and other installations requiring maximum protection. This compact integral assembly with an extremely short lay length provides versatility and simplifies new and retrofit installations which are advantageous in areas of limited space. This assembly consists of threaded quarter turn ball valves, angle union connections, test cocks, spring loaded Y pattern check valves and one hydraulically dependent differential relief valve.