Water resources in the arid southwest are frequently the subject of arbitration between competing interests of private and public entities. Although the legal remedies allow for a path forward, the technical nature of the problem often determines the future success of any solution. The term technical used here encompasses: 1) the hydrogeological properties of water quantity, availability, distribution, and 2) the geochemical issues of water quality, transport and migration, contamination, or mixing with lower quality reservoirs. These examples of multi-use issues change over time and could negatively impact another water user or natural resource. One successful approach can be the inclusion of all agencies early in the technical evaluations from data collection to interpretation, and in addition, to include private sector firms with state of the art investigative techniques.