Not pervious; not admitting of entrance or passage through; as, a substance impervious to water or air.
Not susceptible of being passed through, or penetrated. Generally refers to the percolation of water.
A solid that does not allow a liquid to pass through its surface; impenetrable.[xii] In this context it refers to the ability of rainwater to pass through unnatural surfaces around and near a building or the building's parking lot.