Tell us about yourself!
After reading the comments I see that there are people who do not understand how the plumbing in this works. After flushing, the clean drinking water that comes from the water line connected to the back of the toilet flows out of the top faucet (same water as your kitchen sink) this cleans your hands and falls into the top tank of the toilet. Then the next time you flush, the hand washing water that was stored in the top tank drops down to flush the lower toilet bowl. Completely heigenic!
The handwashing water comes from the house's main water line (pressurized) not the tank.