Saline aquifers appear to have promising storage capabilities for freshwater supplies. Such aquifers would be a practical alternative to surface water reservoirs in areas where natural reservoir sites are scarce or where evaporation might consume a substantial part of the water stored. A single experiment in Virginia more than 20 years ago shows that a substantial amount of freshwater injected into the saline aquifer can be recovered. Environmental factors that affect water recovery are dispersion and mixing at the fresh‐saline water interface, reshaping of the interface because of density differences of the fluids, and groundwater movement in the saline aquifer system. Investigators have shown mathematical approaches to estimating the first two factors. Available data indicate that the third factor may be significant. Feasibility studies of storage facilities should include evaluation of at least these three factors.