Contents damage caused by sewage blockage

Hi – I’m in Vic and am chasing some advice on liaility for damage caused by a sewage blockage.

We notified the owners corp manager immediately on noticing sewage bubbling up from a drain embedded in the floor. Multiple plumbers were called out over a period of 3 days to locate the blockage, which wound up being out in the water authority asset and was caused by either tree roots or a build up of construction debris / crushed rock which we suspect to have been left over from some recent road works.

It took the OC appointed plumbers an incredibly long time to find the blockage (they didn’t have the correct equipment or any current sewerage plans, which didn’t help) and they wouldn’t turn off the water to the complex in the meantime – meaning that our apartment was gradually inundated with sewage. This was exacerbated by a non-responsive OC manager who failed to appreciate the seriousness of the problem despite constant appeals from us.

The strata building insurer is so far being really great but while our contents insurer has taken an inventory of our furniture and recorded it all as being unsalvageable, they don’t cover damage indirectly caused by tree roots so we will be out of pocket if our claim is rejected on that basis. Is there any likelihood of being compensated by another party (e.g. the water authority, local council, or the OC) for our ruined belongings?