Injection of purified water into a groundwater aquifer can lead to geochemical reactions such as mineral dissolution, oxidation, or desorption. The potential for oxidation or mineral dissolution to occur can be mitigated through purified water post-treatment stabilization prior to injection. Geochemical characterization of potential aquifer soils in the injection area can provide the data needed for geochemical modeling and to design an effective water purification process. The geochemical characterization work summarized herein includes conducting soil leaching analysis under "worst-case" scenario conditions to establish a baseline if post-treatment stabilization was not carried out on the purified water. Understanding the baseline, worst-case scenario can aid in establishing and optimizing the post-treatment stabilization regime for the target groundwater aquifer.