As(III) and As(V) as well as mixed forms of the same could be effectively scavenged by a composite with fast kinetics allowing the creation of an affordable arsenic-free drinking water solution for point-of-use applications. The granular composites, composed of iron oxyhydroxide-chitosan nanostructures, were synthesized by a green synthetic route, which in general involves the hydrolysis of a metal precursor-chitosan complex using an alkaline medium followed by washing and drying at ambient conditions. Metal ion precursor used for the preparation of the composite was Fe3+. All syntheses were carried out in deionized water, while natural ground water or tap water was used for testing. An iron oxyhydroxide-chitosan nanostructure was synthesized. 25 mg of confined metastable 2-line ferrihydrite (CM2LF) was shaken with 100 mL of natural tap water. Arsenic removal efficiency of CM2LF was measured by spiking the natural tap water with As(III) and As(V) separately. Thereafter, the water was left standing for 1.5 h and subsequently the leftover arsenic concentration in treated water was analyzed using inductively coupled plasma mass spectrometry (ICP-MS) after acidification with 5% HNO3. Experiments with water filtration cartridges are described in the main Text. The unprecedented large capacity in field conditions is attributed to the inherent structure of the composite with confined metastable 2-line ferrihydrite in biopolymer cages, which allows the creation of effective adsorption sites. The arsenic adsorption capacity of the composite is 1.4 to 7.6 times better than the available compositions.