Which law in China stipulates that residential housing maintenance should be charged?

According to the property management regulations, the property service enterprise should carry out maintenance on the parts used by the property, but the on-site maintenance belongs to the special service provided by the property service enterprise for the exclusive part, and it needs to be charged.

The charging standard for special services shall be charged according to the stipulations in the previous property service contract. Property companies shall not unilaterally raise the charging standards.