One of the major priorities established for the fiscal year 1979 Water Reuse Research Program of the Office of Water Research and Technology (OWRT) was the determination of existing and potential legal barriers to water reuse, and the development of solutions to the identified barriers. Brown and Caldwell was selected by OWRT to investigate the potential legal liability of proprietors of reclaimed water systems under existing civil law in the five arid western states, and to propose model regulatory procedures and legislative enactments that would overcome those legal barriers. This paper is based on the report that has been prepared in response to that assignment.