The contamination of arsenic in human drinking water supplies is a serious global health concern. Despite multiple years of research, sustainable arsenic treatment technologies have yet to be developed. This study demonstrates the intrinsic abilities of cupric oxide nanoparticles (CuO-NP) towards arsenic adsorption and the development of a point-of-use filter for field application. X-ray diffraction and X-ray photoelectron spectroscopy experiments were used to examine adsorption, desorption, and readsorption of aqueous arsenite and arsenate by CuO-NP. Field experiments were conducted with a point-of-use filter, coupled with real-time arsenic monitoring, to remove arsenic from domestic groundwater samples. The CuO-NP were regenerated by desorbing arsenate via increasing pH above the zero point of charge. Results suggest an effective oxidation of arsenite to arsenate on the surface of CuO-NP. Naturally occurring arsenic was effectively removed by both as-prepared and regenerated CuO-NP in a field demonstration of the point-of-use filter. A sustainable arsenic mitigation model for contaminated water is proposed.