The flow of water in a medium in a direction opposite to normal flow. Flow is often returned into the system by backflow if the wastewater in a purification system is severely contaminated. Other reasons for backflow occurrences can stem from poor hydraulic conditions within the water treatment system. For this reason, it is normal for the contaminated water to flow in the opposite direction of which is desired, specifically in ill-equipped systems. Water distribution systems that suffer from this effect produce the likelihood of releasing polluted water that could be detrimental to water users. WHAT CAUSES BACKFLOW? The primary cause of backflow is arguably related to cross-connection issues that increase the possibility of bringing contaminants into the water drinking system. Polluted water is also more likely to be allowed into the system when the pressure in the water tank is lower than the water system’s pressure. Lastly, the occurrence of back pressure can become another cause of backflow. Backpressure is present when the water pressure is greater than the structure that is connected to a public water system that forces polluted water into the system.