When the soil, earth or improvements of one property move onto the adjacent property, either through rain, wind or other natural event, does any liability, or responsibility, occur as well? The Supreme Court set forth the initial rule of law in California back in 1966, holding that an adjacent landowner must “accept the surface water which drains onto his land,” but that the upper landowner cannot alter the drainage system to increase the burden.

Put simply, the law is that the lower,  or adjacent landowner cannot complain of water coming onto his property naturally, but if his neighbor alter the drainage, or increases the flow, liability may result. In effect, a neighbor’s retaining wall, draining canals, concrete driveway or other property improvements may create liability for property damage to his neighbor that suffers harm from the increased water flow and earth movement.       As the Supreme Court held, “There is no question that one’s liability for interfering with surface waters, when occurred, is a tort liability.”

Even if the upper or adjacent landowner’s conduct is “reasonable,” he must accept the harm from increased water flow, as long as the lower landowner’s actions are reasonable as well. This means in effect that even reasonable conduct, such as pouring driveways, creating retaining walls, or adding drainage to your property, may create liability of the water run-off to  your neighbor’s property is increased as  a result.

Government Liability

Generally, the law is that public entities are not liable for damages or injuries to property caused by the land failure of public lands from a natural condition of the unimproved public property. Land failure means any movement of land.  There are exceptions, however, to the governmental protection from land failure or soil movement from unimproved public lands.

If the public entity knew, or should have known, of the probable damage that is likely to occur to adjacent private property because of public land failures, but the entity did not provide a reasonable warning of the danger to the affected property owners, the public entity is no longer protected. Also, if the governmental entity creates improvements that affect the drainage to neighboring properties, liability may result.