This horse may not be dead yet, so a quick note. Rain water should not be a problem, it is distilled (de-ionized) and it is not a conductor. On the other hand out of the tap, dirty or salty (including bathtub) water is an electrolyte, albeit weak, and will conduct. Remember reading about all those sea water flooded Teslas that caught fire after hurricane Sandy?
I would not worry about it too much, but I would use a plastic bag myself, or some simple cover. Spraying WD40 on the cord ends may be useful as well.