Tap water payment business model

This month's water bill has arrived. I used to find it strange when I first saw the water bill, because in addition to the water bill, there is also the drainage fee. I am used to it now, and it is not surprising. But it is not that simple. It is not boring to let us go into it.
First of all, the water company only provides tap water and does not deal with drainage, it should not have the right to charge drainage fees. Of course, he wants to accept us, and the little ones have to hand in.
Second, how to calculate the displacement? The sewer pipe is not equipped with a water meter, so it is impossible to accurately calculate the displacement. The tap water company also knows this. Therefore, the displacement on the bill is estimated based on the percentage of water consumption. This is also reasonable, and there is no way for the small people.
In fact, there is no need to discuss whether the drainage fee is unreasonable. You can simply change your understanding, that is, the actual water fee is not the price announced by the water company, but a percentage is added. The hateful thing is that the water company is the most hateful if it is not expensive.
As a result, the price of a taxi in Nanjing is 1.40 yuan per kilometer, but the actual fare is 2.10 yuan per kilometer, because 50% of the return fee is required. If it is open to the wilderness, the return fee is also excited, but it also needs to be collected when it is open to the city center. That is to say, the actual fee is 2.10 per kilometer. When I first arrived outside China, I thought the taxi was cheap. I only knew it when I sat down. It was not cheap.
This phenomenon can be called a business model or a good customer.