In an attempt to quantify the uncertainties accompanied by radar based precipitation estimation, an empirical approach is developed for the twin X-band radar system of Bonn and Jülich. Figure 1 shows the overlapping radar volumes of both radars in all available elevation angles. A resemblance factor for each cross section, accounting for the percentage of overlap, the time difference between measurements, the level of corrections applied to the raw measurement value and more, is used to determine the expected level of parity between reflectivity values of overlapping radar volumes. For volumes with a high resemblance factor the remaining difference after all correction and filtering procedures is attributed to the random measurement error. A study focusing on different meteorological conditions and precipitation events will produce an empirically based uncertainty value attributed to prevalent conditions that can be applied to each measurement value.