Histograms of the sky-projected distance of water masers from the radio continuum peak, for all the observed masers in the POETS targets (main) and for a maximum continuum-maser separation of 3000 au (inset). Considering all the observed masers, the target-average distance error and corresponding standard deviation are 182 and 16 au, respectively. Selecting masers within 3000 au from the radio continuum peak, the target-average distance error and corresponding standard deviation are 108 and 17 au, respectively. Correspondingly, we used bins of 200 and 100 au for the histograms in the main plot and in the inset, respectively. The histogram values are normalized by the total number of selected water masers.