What is backflow contamination




Backflow Contamination - Cross connection

A cross connection is simply a direct arrangement of a piping line which allows the mains water supply to be connected to a line which contains a contaminant.


		An example is the common garden hose attached to a tap with the end of the hose lying in a bucket containing garden chemicals. Ironically, the ordinary garden hose is the most common offender as it can be easily connected to the potable water supply and used for a variety of potentially dangerous applications. Other examples are where the supply lines are connected to bottom-fed tanks, supply lines to boilers etc.


		Customers of a bank in Georgia USA were surprised to find yellow water flowing from the drinking fountains and green ice rolling out of the dispensing machines. It was later reported that a pump used for the air conditioning system had burned out; and the maintenance man, unaware of the danger connected the system to another pump used for drinking water. The result caused large doses of bichromate of soda to be forced into the water supply, causing the dramatic appearance of yellow water and coloured ice cubes.

Backflow Contamination - Cross connection