Does the indoor sewer leak belong to the scope of property management and maintenance?

The first is the question of fees. The property management company is responsible for the maintenance, conservation and management of public pipelines, and the owner is responsible for the maintenance of its own pipelines. According to your description, the dredging equipment used by the property management company is from the "horse gourd" outside the building to the building, not from the indoor kitchen sewer, which indicates that the buried crossbar of the main sewer in the building is probably partially blocked. This part of the maintenance costs should be borne by the property company. (Note: the warranty period of the construction unit is one year, and the property will be responsible after one year). If it's a new building, it's likely that the joint (elbow) between the upright and the crossbar is blocked by sundries. According to your description, it is probably blocked by foaming agent or cement mortar and cannot be removed by dredging equipment. I hope this helps.