Different laws apply to the entry of different kinds of objects. Water flowing from one neighbour's land to another neighbour's land as a result of natural events and situations (rain, floods, slope of the land and so on) does not normally involve any legal issues. Where a flow of water from a neighbour's land on to the occupier's land is caused by the neighbour, this may be with or without permission.
A typical situation involving permission (often permanent) is a drainage easement. The easement would normally be written into the land title documents. If the flow of water occurs without the occupier's permission, and was caused directly or indirectly by the neighbour's own activities, the occupier may have a legal right to sue the neighbour in an attempt to prevent this occurring again, and to receive compensation if appropriate.
This right will exist in four situations:
- where the flow was intentional ("trespass"), for example, where a neighbour deliberately directs a hose on to the adjacent occupiers land;
- where the flow occurred in the course of another activity, for example, a garden sprinkler, over-flowing drains, running taps, modification of normal watercourses like a river or stream;
- in some cases, where the flow was accidental and caused damage, even without carelessness by the neighbour; and
- where the flow has been caused by the negligence of the neighbour, and it causes some damage to the occupier, for example, because of the careless construction of a tank or dam.