Treatment of drinking water for arsenic (As) removal has been implemented in centralized facilities worldwide, reflecting the increasingly stringent national and international drinking water standards for As, for which a standard of 10 mu g/L has been widely adopted. It might therefore be expected that information on the performance of installed treatment processes could serve as basis for process optimization and more-informed decisions on process selection. A review of available information on installed treatment does provide some insight into the scale of implementation, factors driving process selection and difficulties that have arisen in practice (as a complement to more accessible information on bench-scale and pilot-scale studies). The availability of information on treatment performance at full-scale treatment is, however, severely limited. The rapid advances in information technology and consequent elimination of technical barriers to sharing information and knowledge should allow the development of an international, accessible database or even a metadata portal for installed technologies for As removal that would offer the potential to benefit from past and ongoing experience in practice.