The major purpose of taking Onsen is not only to wash ones body but also to rest and relax by soaking Onsen. No drunk person inside the bathtub. Usually, the temperature of Onsen is at least 40degrees (40℃). So it is not good for your health for heavy drunk person to take or soak the bathtub.
Why is onsen popular in Japan?
Experience the nature - Most onsen are located in areas that are rich in natural beauty. Open air bath or Roten buro (in Japanese) is one type of onsen that is very popular because you can relax in a hot spring while enjoying the view of mountains, ocean, trees, river, snow, and so on.
Why do people use onsen?
The onsen is the ultimate bathing experience. The hot spring water can relieve tense muscles and the natural or serene surroundings of most Japanese hot springs can help clear your mind. Your body quickly cools after leaving the hot spring which encourages your body to relax and put you into a deeper sleep.