As a master plumber, plumbing contractor and plumbing engineer I am required to protect the health of the nation by keeping our water supplies safe for this and future generations.The continued pollution of our water sources caused by early sewer design in our metropolitan areas is the greatest threat to our most important resource: WATER. Cities are prevented from addressing and correcting this problem because of infrastructure and financial constraints. Although progress has been made with expensive civil engineering solutions, they cannot work properly until we optimize the current infrastructure.The cost effective solution to minimizing this problem is to modify our existing flat roof buildings in these areas into passive "Blue Roofs" that reduces the storm water flow rates in the Combined Sewer network.By reducing the storm water flow rates it turns the 100 year storm plus into a 10 year storm that allows the civil engineering solutions to work as designed.Turning an existing flat roof into a passive "Blue Roof" can be as easy as restricting the water from entering the building's roof drain piping.That is why I and my fellow plumbing experts with decades of experience have designed the "RESTRICTOR".It can turn an existing flat roof structure into a "Passive Blue Roof" without architectural or structural modifications in minutes. Thus reducing the flow rates in the existing combined sewers and waste water treatment plants.Winston Churchill once said, “Out of intense complexities, intense simplicities emerge.”