My point is that the OC might not have any liability at all.
That’s a common situation in VIC where lot owners are typically responsible for much of the waterproofing of their lot. And they can sometimes accidentally cause the flooding of their lot.
Much of the resulting damage can be covered by strata insurance which covers more than just common property. But the OC itself might not be liable.
In my stratas in VIC, the above situation has happened many times.