You mean the housing maintenance fund, right? Every city has a charge, and each city may be different according to the percentage of the total house payment. Normal commercial housing has a housing maintenance fund for future housing maintenance, such as waterproofing. This money belongs to the public and is kept by the property. You can't spend it without the owner's signature.

When you say someone doesn't pay, is it the kind of public rental housing subsidized by the government, or the welfare housing allocation, or the housing allocated to employees by factories and mines, which may not be paid?