In assessing the rights of surface water use, what is the natural flow theory?

The natural flow theory in surface water law says that property owners cannot interfere with the natural drainage patterns of surface water, meaning you can’t redirect or block the water from flowing the way it normally would across your land. For example, you can’t build a dam or drainage ditch that causes water to flood your neighbor’s property.

However, most states have moved toward a more flexible version of this rule, allowing reasonable changes to natural drainage patterns. As long as the modifications are considered reasonable and don’t cause significant harm to neighboring properties, landowners can make adjustments, like improving drainage for farming or construction.

So, under the natural flow theory, the main idea is to respect how water naturally flows across the land, but there’s some wiggle room for reasonable changes, especially if they benefit the land and don’t negatively affect others.