I don't know. There is a removable part in the top that we clean. The top itself appears to be sound. The unit has done this almost since new, years now. The rice comes out fine each time. There is also some bubbling out of a vent that is part of the top, but this is not the source of this pool of whitish water under the unit. It does not affect the operation of the device, but I sure would like to know what is causing it just because I like to know how things work.