This dataset includes the measurement of COD, EC, Turbidity, TSS, NH4, and NO3 of rainwater samples from three different catchment areas in Hanover, Germany, collected from October - December 2022 and the results of treatment of this rainwater with a Gravity Driven Membrane Filtration and a Sandfilter equipped with activated coal. More information including sampling and analytical methods are detailed in the corresponding journal paper "Using stormwater in a Sponge City as a new wing of urban water supply – a case study" in the MDPI journal "water".