Discovery 6

I think I know how a shower works. The pipes that are connected to the shower have metal cups. The pipes bring water into the metal cups in the morning or 8:00pm--10:00pm. The handles are connected to the metal cups so if you turn it, the cups will tilt  and the water will spill. The more you turn it, the more water will spill over night. I imagine that someone replaced the cups at night.