The injection of reactive liquid wastes into underground disposal reservoirs will impair permeability. Permeability and hence the capacity of a reservoir to accept wastes without resorting to excessive input pressures can be improved by several restoration techniques including reaming of the face of the borehole; and chemical treatment by injection of acids (such as dilute hydrochloric). Underreaming of the borehole in the laboratory investigation was effective. In designing liquid waste disposal systems, laboratory studies employing reservoir rock specimens and samples of the waste to be injected may lead to the selection of appropriate and effective procedures for permeability restoration. The capacity of the reservoir to accept a given volume of waste within the design criteria for pressure requirements should then contribute to the economic feasibility of this method of waste disposal. A broader use of underground waste disposal will complement the national effort to rid surface streams of their role as carriers of noxious wastes.