Observations in singlepoint chopping mode of the 82,7-73, ortho-H216O were carried out toward NGC7538-IRS1 (RA=23:13:45.3 (J2000) DE=+61:28:10.0) as part of SOFIA Cycle 3 project on 2015 December 9, using GREAT. At the systemic velocity of NGC7538-IRS1, the system temperature was typically 2000K (SSB) and signal-band zenith opacity 0.08. The on-source integration time was 20-min. The chop throw was 100" to either side of the on-source position (chop-nod method). One channel (L1) of GREAT was tuned to the 1296.41106GHz water line frequency (lower sideband LSB), the other channel, the LFA (Low Frequency Array) 7 pixel array, was tuned to the [CII] 158um line. In order to constrain the maser models, and because of the variability of the maser emission, nearly contemporaneous observations of the 616-523 transition of ortho-H2O (rest frequency 22.23508GHz) were carried out on 2015 December 11 (integration time on source of 15-min) with the MPIfR 100-m telescope at Elsberg, Germany. Interferometric observations of the same source of the ortho-H2O 616-523 line emission were performed with e-MERLIN (commissioning observations) on 2016 April 20. These were the first-ever 22GHz images made after the e-MERLIN upgrade. (2 data files).