自来水、瓶装水、过滤水……饮水选择越来越多，哪种更优？

Group 1 - The article emphasizes the increasing public concern over drinking water safety due to rising living standards and health awareness, particularly regarding the presence of scale in kettles [1][2] - Many citizens express worries about the health implications of consuming water with visible white floating particles, leading to a perception that tap water is of poor quality [2][23] Group 2 - Scale, commonly found in kettles, is a normal phenomenon resulting from the precipitation of dissolved minerals (mainly calcium and magnesium ions) when water is heated [5][7] - The hardness of water, which refers to the total concentration of calcium and magnesium ions, is a key factor in the formation of scale, with higher hardness leading to more scale [8][28] Group 3 - Drinking water with scale does not increase the risk of kidney stones, as the primary cause of kidney stones is concentrated urine, not the hardness of water [9][10] - The World Health Organization states there is insufficient evidence to suggest that drinking hard water increases the risk of kidney stones [10][30] Group 4 - While scale is harmless, it can reduce the heating efficiency of kettles and affect their appearance; however, it can be easily removed using vinegar or lemon [12][31] - The article explains the rigorous purification and delivery processes that tap water undergoes before reaching consumers, ensuring its safety [13][32] Group 5 - In China, tap water is produced according to strict national standards, ensuring its safety for consumption after boiling [40] - The article discusses various drinking water options available in the market, including bottled water, filtered water, and tap water, highlighting that all can be safe if they meet hygiene standards [39][40]