After WWII, most people couldn't afford to have bathrooms in their house, thus the development of communal bathhouses. People didn't go to the bathhouses to get clean, they went to gossip and have fun. Bathhouses were commonly integrated, but today, the tubs are segregated by sex. The ritual of bathing is also special. Asian bathrooms are not like American bathrooms, there is a nice drain on the ground, and all the surfaces are tiled.
People soap up, scrub, and rinse without getting into the tub.
They then fill the tubs up with water a few shades below boiling, and relax for a long time. So, you would already be sparkling clean by the time you got in the tub. Today, bathing is a resort activity. People travel to famous bath resorts, and bathe for days. These resorts are usually hot springs, and mineral springs, the type famed for health or something equally relevant.