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Questions surround the connection of luminous extragalactic masers togalactic processes. The observation that water and hydroxyl megamasers rarelycoexist in the same galaxy has given rise to a hypothesis that the two speciesappear in different phases of nuclear activity. The detection of simultaneoushydroxyl and water megamaser emission toward IC694 has called this hypothesisinto question but, because many megamasers have not been surveyed for emissionin the other molecule, it remains unclear whether IC694 occupies a narrow phaseof galaxy evolution or whether the relationship between megamaser species andgalactic processes is more complicated than previously believed. In this paper,we present results of a systematic search for 22 GHz water maser emission amongOH megamaser hosts to identify additional objects hosting both megamaser. Ourwork roughly doubles the number of galaxies searched for emission in bothmolecules which host at least one confirmed maser. We confirm with high degreeof confidence ($> 8 \sigma$) the detection of water emission toward IIZw96,firmly establishing it as the second object to co-host both water and hydroxylmegamasers after IC694. We find high luminosity, narrow features in the waterfeature in IIZw96. All dual megamaser candidates appear in merging galaxysystems suggestive that megamaser coexistance may signal a brief phase alongthe merger sequence. A statistical analysis of the results of our observationsprovide possible evidence for an exclusion of H$_2$O kilomasers among OHmegamaser hosts.

The Hydroxyl-Water Megamaser Connection. I. Water Emission Toward OH Megamaser Hosts