Backflow means intermixing of contaminated water with clean drinking water. Obviously backflow, wherever it happens is detrimental to health as it contains filthy liquids and other dirty and dangerous substances. It generally happens where the water pipe is damaged and is close to drain or sewerage pipe. Chances are that polluted water seeps into fresh water supply system causing backflow to take place. Backflow can occur in any building, big or small, or in a factory where there is a possibility of “cross-connection” within the water pipes system.
Usually the drinking or potable water flows into the pipes with certain pressure which does not allow the contaminated water outside to mix up. But as and when the pressure of water inside the pipes subsides, the outside dirty water is sucked into the drinking water pipe. This is commonly referred to as backpressure or back-siphoning, as detailed below.
An example of backflow occurring
There can be any number of instances of cross-connection hazard known as backflow. For example, just consider that one end of your garden hose is attached to water tap and the other end is dipped down into a bucket of liquid pesticide. Suddenly, the water supply is snapped and the water pressure inside the pipe drops down abruptly. What happens is that some of the pesticide is sucked into the pipe and it contaminates whole of water in the pipe. In Brisbane Eastern Suburbs such pressure drop-downs are quite common and keep on happening time to time and these cause a reverse flow in the water line. If the water supply system is not fitted with backflow prevention system the contaminated liquid will keep getting into your main water supply system.
Backflow prevention device will stop the reverse flow and keep your water from getting contaminated.