Backflow is where the contents of your hose can get back into your drinking water. A hose left connected to a garden tap could potentially become submerged in water at ground level. As a result, dirty water could potentially siphon back into the water system, contaminating the drinking water supply.
In order to protect the drinking water supply in your home from contamination due to backflow,) a Double Check Valve is supplied with all of our taps. The Double Check Valve prevents backflow, as it only allows water to flow in one direction.
To meet the requirements of the Water regulations (which are law), all hose union taps in domestic gardens are to be fitted with a Double Check Valve.