What is the fine-grained topic of the following text: The difficulty is that each of their rooms (so far) contain only 2 water sources ─ 1 showerhead and 1 set of separated taps as follows ─ but the red space between the taps is always too narrow and tiny to support anything, much less a water filter. Only return the topic.
Difficulty in fitting a water filter due to limited water sources in a room