Many planned and unforeseen occurrences can cause a pressure drop that may lead to a backflow or back siphonage incident. This includes firefighting efforts, main breaks and repairs. If a pressure drop occurs in the water distribution systems, any connection to a non-potable water source could be siphoned back into the customer’s drinking water piping, polluting the water within the home, and even into the water mains in the street, polluting the public water system. The only way to prevent such incidents from occurring and to maintain safe drinking water is to use backflow prevention devices and to make sure that they are correctly installed and adequately maintained.