El Paso relies on three sources of water supply to meet its potable water supply needs. These three sources are the Rio Grande for surface water and Mesilla and Hueco Bolson for groundwater. The Rio Grande source averages about 4-6 ppb and is largely removed during surface water treatment. In the Mesilla Bolson the majority of wells have elevated arsenic levels averaging about 17 ppb and treatment will be centralized utilizing a different approach under a separate program. In the Hueco Bolson, the largest aquifer, arsenic is intermittent and spotty. This paper is about he Hueco Bolson Aquifer and four of its eight well fields (Northeast, Cielo Vista, Eastwood and Lower Valley) impacted by the Arsenic Rule. The Hueco Bolson is a critical source of drinking water and represents an average production capacity of 42 mgd and peak sustainable capacity of 50 mgd. Pilot Studies conducted by EPWU indicated that an adsorption media system for arsenic removal would be easy to operate, has limited residuals handling requirements, minimizes chemical handling and assures process integrity.