NOEMA spectra of the three z > 6 quasars J2310+1855, J1148+5251 and J0439+1634 (from top to bottom). We report the observed data in light blue and the best-fit models in red. The blue dashed lines indicate the rest frequencies of the targeted H₂O transitions (quantum numbers are also reported). At the bottom of each spectra, we report the residuals (data-model). The gray-shaded areas show the noise RMS across the spectra.