Since soil and groundwater are not directly exposed to the surface environment like surface water or the atmosphere, their pollution has the characteristics of concealment and uncertainty. This makes it difficult to define the contaminated area and scope, which increases the difficulty and cost of repair.
At the same time, the incomplete domestic legal system is another major reason why soil and groundwater pollution cannot be managed in a timely manner. It is difficult to clarify the party responsible for the land, and the bankruptcy of some responsible polluting industries makes it difficult to implement the "polluter pays" principle, resulting in site restoration often troubled by funding sources.