This 1 inch N pattern bronze reduced pressure zone assembly backflow preventer prevents 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. 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, test cocks, spring loaded Y pattern check valves, and one hydraulically dependent differential relief valve. This backflow assembly contains a flood sensor with SentryPlus Alert(R) technology to detect excessive water discharges from the relief valve. When activated through an add-on sensor connection kit, the flood sensor can send an alert to notify personnel about potential flooding. Add-on sensor connection kits are available for BMS and cellular communications.