Property leakage repair responsibility

Hello, My query is that, there is a leakage taking place on the bathroom walls due to the flat above my apartment. This is the second time it is reoccurring. The previous water proofing repair charges were shared equally between the earlier tenant and me, after discussing with the owner of the above flat. However, since the tenant has changed and the leakage is reappearing. In such a case where the earlier cost of repair was shared equally and the fact that, the above flat is being rented out time and again, would it be sole responsibility of the owner of the above flat to get the repairs carried out or would I have to bear the costs equally again? Thanks