What are the feng shui taboos for changing the master bedroom bathroom into a study?

Without water, there is no need to be waterproof. If you want to put a cabinet inside, you can brush a layer of waterproof paint on the back of the cabinet. However, I personally suggest not to change the bathroom into a study, because the bathroom is a space for family members to excrete and bathe, which is not clean in essence, and it is a gloomy place, while the study is a place where people learn and grow up. Setting the study in the bathroom, upstairs and downstairs are bathrooms, will affect people's study and work, which is a taboo in Feng Shui. And the light in the bathroom is also very poor. Suggest studying in another place.