Check that the floor in wet areas, bathrooms, laundrys, is lower than that of the rest of the house, and that the tiling is drained towards the floor waste. Also that the flexible pipe under sinks, tubs, wash basins is in good condition, and of good quality.
I recently had the upsetting, inconvenient and costly experience of a pipe bursting, flooding half the house. The abovementioned practise would alleviate much of this and was the practise years ago. My place in Yamba, was built by a large reputable company. A number of the neighbours have had the same experience.
Bob Faulkner, Yamba