There's no harm whatsoever from the water. The only (small) risk is a power surge from the house direction if its connected. With the timer switched to off, or the breaker flipped, it is effectively disconnected and can be left connected to the power center.Also why would leaving it all connected be thea a wrong thing to do? Will it damage the cell? I kinda figured it would be fine since the cell is just showing the cold water light.