Opportunities exist to use electrodialysis in a variety of applications. These are of particular interest in the cleanup of brackish groundwater, both as a primary technology and as a reject concentration and recovery device. This paper assumes the reader is familiar with the basic process of ED system operation. The author covers applications of ED (boiler water production or brackish water for potable use), membrane properties, desalination ratio, design formulas, preliminary design strategy, and alternative process flow schemes. Figures show the principles of multicell electrodialysis process, the material transfer in electrodialysis, concentration versus time graph, salt passage ratios, desalination ratio versus stack production, definitions, formulas and calculations for system design, and design decision trees.