Water will do it in the wrong place. But also make sure your water has a neutral ph. Also the room it is in has no acidic fumes/vapor of any kind. Like acid storage or even a base like chlorine storage. Both will make a very conductive surface.
Personally, I would take a good DVOM and start isolating your ground pin/chassis for a current path with the ohm function and L1. Should be infinate. If not, you have to disconnect one item at a time to isolate where the problem is. Be it a solenoid valve, harvest assist, pump motor, Compressor winding, sensor, or control board. The likely problem is often the pump motor if you have under treated hard water. It work's in the worst environment of the machine. Also, if your machine is in a unconditioned space, and some of the insulation is missing or not properly installed, there will be condensation that gets where it doesn't belong.