Hi, my neighbour directly behind me is building a new house and in the process the builder/plumber has disconnected our sewage pipe which is a share pipe with the neighbour's. We only found out because our toilets became blocked and is mow overflowing at the gully. We got a plumber in to investigate and found out that our sewage line got disconnected at the neighbours construction site. we talked to the builder and the neighbour and they are saying it is not their fault as the sewer pipe was not where it was suppose to be on the sewage diagram and that when they disconnect it, it was dry. I rang sydney water and they said its a civil dispute so they have nothing to do with it and they also mentioned that legally the neighbour can disconnect us? the question is can they?