You are talking about the housing maintenance fund, right? It is charged in every city, and it may vary from city to city according to the percentage of the total house payment. Normal commercial housing has a housing maintenance fund, which is used to maintain the house in the future, such as waterproofing. This money is public and is kept by the property. It cannot be spent without the owner's signature.

when you say that some people don't pay, are you talking about public rental housing subsidized by the government, or welfare housing distribution, or houses distributed by factories and mines to employees, which may not be paid?