We have used continuous- wave cavity ring-down spectroscopy to record a band with origin close to 7273.5 cm(-1) in a Kr supersonic expansion seeded with H2O. It is assigned to v(1) + v(3) <- GS, Pi (1(01)) <- Sigma(0(00)) in Kr-H2O. Several lines of the four most abundant Kr isotopic forms are resolved. The rotational structure (T-rot = 18 K) is analyzed and the lines fitted (sigma < 0.0004 cm(-1)) together with literature microwave data. The mean upper state predissociation lifetime is estimated to 4 ns. (C) 2014 Elsevier B.V. All rights reserved.