Water suppliers may be familiar with small-scale aquifer storage and recovery projects but typically are unaware of the potential for using large-scale groundwater storage projects as an alternative to construction of new surface water supply reservoirs. Jones examines the demonstrated feasibility of implementing large-scale groundwater storage projects, and the infrastructure and institutional arrangements needed for their implementation. Large-scale groundwater storage projects have been successfully implemented in California. Access to preexisting regional water conveyance infrastructure providing a source of imported water is a key factor enabling many of these projects. Among other western states, only Arizona and Nevada now have projects similar in scope to those in California. However, state financial assistance provided to local agencies implementing groundwater storage projects is encouraging development of new projects. By giving consideration to groundwater storage alternatives in long-range master planning, utilities can preserve their ability to implement such projects in the future. Includes 29 references, tables, figure.