A 15-month pilot-scale study of nitrate removal from drinking water by ion exchange (IX), reverse osmosis (RO), and electrodialysis (ED) was carried out in Glendale, Arizona, where the raw water contained 18 to 25 mg/L NO3-N. The experiments were carried out using the University of Houston/U.S. EPA Mobile Drinking Water Treatment Research Facility. All three processes could readily reduce the nitrate level far below the maximum contaminant level of 10 mg/L NO3-N. For the desalting processes, the polyamide RO membrane performed better than cellulose triacetate on the basis of nitrate rejection--94% compared with 76%, respectively. Regeneration of the nitrate-laden resin was studied extensively using complete regeneration, partial regeneration, and regenerant reuse. For complete regeneration, the more dilute the regenerant, the more efficient it was. Partial regeneration, consumed 37% less NaCl than the most efficient complete regeneration. Regenerant reuse and counterflow regeneration were not effective.