The reaction of Criegee intermediates with water is one of the dominant removal mechanisms for these species in the atmosphere. The reactivity of alkyl substituted Criegee intermediates has been shown to be affected by the nature and location of the substituents. CH3CHOO, acetaldehyde oxide, can be considered as a prototypical Criegee intermediate with a single alkyl substituent to examine the conformer specific reactivity for Criegee intermediates. Pulsed Fourier-transform microwave spectroscopy has been used to probe the products resulting from the reaction between CH3CHOO and water. The hydrogen-bonded complex between CH3CHOO and water together with the reaction product, hydroxyethyl hydroperoxide, were observed in the discharged plasma of a CH3CHI2/O2/water gas mixture. The experimentally determined rotational parameters support the identification of the complex between water and the syn-CH3CHOO conformer and two conformers of hydroxyethyl hydroperoxide, produced from the anti-CH3CHOO conformer and water.