This dataset contains water chemistry for inlet samples for remediation systems in Bihar, India and associated remediation system efficiency for arsenic removal. The dataset contains paired inlet-outlet data for 31 household and community groundwater remediation systems of different technology types (split into reverse osmosis/RO and non-reverse osmosis) and settings (household and non-household). The chemical data includes the composition of inlet water (concentrations of Fe, P, As, Ca, Mg, Na and Si) and associated arsenic removal. This data was generated as part of the Indo-UK Water Quality Programme Project FAR-GANGA (NE/R003386/1 and DST/TM/INDO-UK/2K17/55(C) & 55(G)). Full details about this dataset can be found at https://doi.org/10.5285/77700f8e-5da6-45ab-9c12-df1a7d20bc32
