This is a response to property.

This sub-case-if it is because your sewer pipe is blocked, which leads to the loss downstairs after the water flows back, then this responsibility should be borne by you; If the sewer pipe is blocked from the first floor, but you don't know that the loss downstairs is caused by the water pouring from your sewer pipe, then this loss should be solved by you, the first floor and the property (there is a favorable condition for you, how can you prove that the sewage overflowing from your sewer pipe crossing is discharged by you? If you can't prove it, then you are not responsible. The first floor can investigate all tenants from you to the upstairs, but you can't just investigate yourself. If the property has known about the pipeline blockage before and has not solved it, then the responsibility will be borne by the property. On the other hand, if you live on the second floor and your sewer pipe is independent of the first floor, even if the blockage is not caused by you on purpose, the responsibility will still be borne by you, regardless of whether you have communicated with the property in advance about maintenance.