Due to prohibitively high cost of inland desalination, there has been a surge of interest into emerging technologies and techniques for recovery enhancement and concentration minimization. EDR has been identified for its potential as a high-recovery desalination technology. This research hypothesis was that EDR could effectively treat brackish groundwaters with high calium sulfate concentration, demonstrating its high-recovery potential for inland brackish water desalination. The full-scale EDR system demonstrated an ability to safely and efficiently treat a feedwater that was nearly saturated with calcium sulfate.