Since March 1988 we have monitored the 22.2 GHz H20 maser line of 12 long period variable stars (LPV) with the 37 m telescope at the Haystack Observatory. We include the two Carbon stars V778 Cyg and EU And. The maser flux from V778 Cyg has varied by at least a factor of 5 from its detection level of 1.9 Jy on 1987 March with a possible period of a year. Figure 1 plots the 22GHz flux as a function of Julian date. We do not yet know whether the period will repeat. V778 Cyg also has shown variations in the intensity (by a factor of - 2) on a time scale as short as 15 hours. The water maser flux from EU And has decreased from its detection value of 8 Jy in 1986 November staying relatively weak at the 2-3 Jy level during the last year. We interpret both V778 Cyg and EU And as binaries, each with an M star component with a thick circumstellar shell and a C star component. The C star is brighter in the visual region where the system is classified whereas the M star is brighter at wavelengths > 5 μm. The circumstellar shell is the source of the strong silicate emission seen in the IRAS LRS spectra and of the water maser emission.