Most big cities, the capital, are built by water, so each city has a canal, which has a relative hydraulic engineering and hub structure to ensure that sewage flows out on one side and new water flows in on the other. This requires a lot of people's consciousness, and it is strictly forbidden to discharge pollutants at will. Those who pollute the environment and do not listen to the command and discharge pollutants at will will be severely punished according to the situation. However, a comprehensive survey of relevant historical data did not say that water charges were charged.

During the Sui and Tang Dynasties, there was its own artificial water diversion. In addition to the river, a diversion canal was dug, and a steady stream of recyclable water resources gave the whole city a steady stream of water to drink. On the other hand, many people may think that most of the water that the ancients drank came from well water, because when we watch costume TV series, we usually put down the bucket and fish it out of the well, which is also very troublesome. Moreover, if some elderly people don't pay attention to drawing water, they may be caught in buckets and drowned in wells. In case of drought or some natural disasters, well water may dry up, and water is an indispensable resource in people's lives. Well water is also the most easily poisoned, and then infected, and even the whole village will be directly destroyed.

In fact, in ancient times, there was actually "tap water", which could be drunk directly without water all year round, which is what we call clear spring. However, these are mostly mountain villages. Generally, there is spring water flowing down from the mountain wall. Water is endless all year round, regardless of spring, summer, autumn and winter. This phenomenon usually occurs in the south, because the humidity in the south itself is high, and then it is warmer all year round, so they usually choose to build a special sink under the spring, and then the water will flow all the time, either irrigating the terraced fields or drinking water directly, which is very convenient.