This is to clearly identify the type of water you want to use before choosing a system of filtration and purification. Water public networks is monitored according to European standards. Sometimes certain regions benefit from exemptions generally understandable to avoid a shortage in supply. In Europe, the regions are not equal in quality of the distributed water or the price paid. As to the rainwater, it is increasingly collected by the population. Of course you have to invest in collection equipment, storage and delivery to use. Apart from the use of this water the garden, and for cleaning the toilet, can we destine such for drinking, cooking, washing, showering and bath? Here are some explanations and some tips in water treatment processes of the public network, water wells, water drilling or collected rain water, not to mention the river water and lake!