The prevention of contamination in any plumbing system especially a domestic one is of paramount importance. Should dirty water make its way back into our water supply, then our health is at a sever risk. Backflow is a means by which the dirty water can find its way into our system. Crystal Palace Plumbers can solve contamination issues.What Causes Backflow?There are generally two causes of backflow in a plumbing scenario and they are:Back Pressure:This is where the water flows in the wrong direction back into the system, for example, if the heating system was of an unvented type, the water heats up and causes a massive pressure increase.Back Siphonage:This occurs as the supply pressure drops lower than the pressure in an external source. For example if you have a garden pond that you have constructed and the pond is higher than the tap with a hose that you use to re-fill every so often. If you were to leave the hose in the pond it is possible unless you have something to stop it that the water may start to flow backwards as it is sucked back, and this could contaminate the water in the home. A Crystal Palace Plumber can diagnose this.Ways Of Prevention:Air Gaps:A nice and easy way to prevent backflow is to create an air gap between the supply outlet and the greatest level of water in any appliance. Check Valves:If the air gap is not achievable, something called a check valve can be used. A check valve is fitted, usually in the supplying tap, and this will only allow water to flow through it in one direction, just like a diode in an electrical circuit. There is something called a double check valve also, this has twice the protection, the second is a back up just in case the first valve fails.