Water is a limited resource in much of Europe. The faucet water is not pure and so people drink and cook with bottled water. The toilets are designed to reduce water use and there are separate buttons for a “hard” (#2) or “soft” (#1) flush (the ‘hard’ and ‘soft’ terms are my own, not local use). American toilets waste a great deal of water; we should use more efficient toilets such as these.