A landowner is entitled to subjacent support which is the absolute right to have one’s land supported from beneath its surface.  If one person owns the surface of the land while another owns the subjacent surface, the owner of the surface is entitled to retain the land in its natural condition without subsidence caused by the withdrawal of subjacent materials by the subsurface owner.

Similarly, an adjoining landowner who taps a subterranean stream during excavation, and causes the soil of the neighbor’s land to subside will be liable for injuries that result.  The surface owner’s right to sue the subsurface owner for deprivation of subjacent support arises when the land actually subsides and not when the excavation is made.

The construction of buildings on the surface of the land does not reduce the right of a person to subjacent support.  However, it changes the circumstances under which that person may recover for the removal of subsurface support. If such buildings are damaged, their owner must establish that the removal of the support was done negligently.

In addition, one who negligently withdraws subjacent support of land in another’s possession or put any artificial additions on it is subject to liability for harm resulting to the other’s land and to the artificial additions on it.