Backflow is a phenomenon where the water got contaminated because of the unnecessary mix of the polluted water. It is a term of plumbing or measuring of the water that is not needed in reverse direction. It is a serious threat to the health of the people because it can cause a severe disease to somebody’s health. It happens when the clean water got contaminated with the dirty one. Some of the cases are mostly that water from the toilet. There are ways to prevent this from happening but usually the easy way is to use the automatic way. Automatic check valves are needed to prevent back pressure, in different situations and different category there are certain valves with certain capabilities that is to be used. The more the category is higher the more valves is to be used in some cases instead of valve air gap is used according to the category. The presence of backflow occur because of two reasons either back siphonage or back pressure.
Back siphonage takes place when the pressure of the supply is lowered below of the system and this happened when the supply is interrupted or drained down, it can be prevented by the use of an air gap. Standards use for the air gaps are based on the amount of separation they provide and their acceptability and capability for the various risk categories.
In other countries where there is a high possibility of backflow. Government approved backflow prevention assembly that gathered to protect water supplies from contamination or pollution due to backflow. As the water entered the pipe there is a certain pressure to attain to enable water to flow smoothly but in some cases when there is a rapid need for water there is a tendency that the pipe leaks causes the dirty water from the grounds or other storage to enter and contaminate the clean one. In order to prevent this from happening backflow prevention device should be observed. The most easy and effective way is to use an air gap; others used valves in accordance to the category it fit in. backflow prevention device ensures that water flows in one direction only.