The purpose of this report is to outline the results of laboratory and field testing of a capacitive deionization system. First, laboratory testing was completed in order to close a mass balance around the Sabrex Electronic Water Purification (EWP) system. Second, simulated coal bed methane water was treated with the EWP. Field testing of a 75 gallon per day EWP took place in Chefornak, Alaska over July 29 – August 5, 2006. The goal of the testing was to determine the suitability of the EWP system for the reduction of high TDS levels in the Chefornak groundwater. Two batches of coagulated and filtered water were treated with the EWP during testing, and measurements for total dissolved solids, color, turbidity, pH, temperature, volume and UV absorbance were collected from the feed, treated and reject water. Lab analysis was also performed in order to determine metals content, alkalinity, total hardness, total organic carbon and total inorganic carbon. Finally, laboratory testing using the EWP was carried out with different natural and simulated waters at the University of Alaska Anchorage. Natural waters tested include raw water from Copper Center, Alaska and Barrow, Alaska. High iron-content water was also treated using the EWP system. Results indicate that the EWP system effectively lowers the level of TDS in a wide variety of waters. Field testing illuminated the dangers of inadequate pre-filtration and demonstrated the quick and effective recovery of the system following an chemical cleaning cycle. Though TDS reduction was dependent on feed concentration and system throughput, 40-60% reduction was typically possible on a 1000 mg/L TDS feed after a single pass through the system. A number of metal species were also removed from the feed water as well, with average removal anywhere from 25-50%. The ratio of permeate to reject is variable depending on flow rate, though is ~1:1 – 1:1.2 during ideal conditions. Power consumption during testing is 7.1-8.3 Whr/gal when standardized to manufacturer throughput rating. The technology appears to be a good option for treatment of water with high levels of TDS in rural communities.