When we travel to some advanced countries, many tour guides always tell us that the local tap water quality is good and we can drink it directly, especially in Japan, the situation is common. But, when we drip 3~5 residue chlorine tester into the tap water, you can discover that the color of the tap water turns to yellow quickly. It means that the amount of residue chlorine is much. We can’t drink tap water directly at all.
And the air pollution is more and more serious, even the river and groundwater are polluted. If the pollutants flow into tap water or the river used as drinking water through those broken pipeline, those water have to be processed by high-tech water filter to drink directly.