Concrete/maghemite nanocomposites were prepared by aging a mixture of magnetite nanoparticles (NPs), sand and Portland cement. Diverse spectroscopies and magnetometry revealed that the nanocomposites incorporate maghemite NPs in the concrete structure. Scanning electron microscopy also revealed the presence of maghemite NPs and variations on the surface morphology of concrete. Regarding the evaluation of the arsenic removal properties of concrete/maghemite nanocomposite, it was found that the addition of the NPs improved the arsenic removal capacity of concrete. Batch studies revealed that the adsorption isotherms fitted to the Gunary isotherm model. Furthermore, column studies demonstrated the application of the nanocomposites for arsenic removal from well water under dynamic conditions. Using the bed depth service time model for the evaluation of the column performance, it was shown that the columns of concrete/maghemite nanocomposites can diminish the arsenic concentration of water from 10 ppm to 10 ppb. By XPS, the adsorption of As(V) species on the nanocomposites was demonstrated. The use of magnetic NPs in concrete demonstrated that the magnetic properties of maghemite are conserved and the arsenic removal capacity of concrete is augmented. Moreover, the nanocomposites can be used in continuous flow systems for arsenic removal from hard water.