A bathroom in the West is not bad, or worse feng shui, than a bathroom in any other feng shui bagua area of the house.
You might have a bathroom in the love area, or in the money area.
You might also have a bathroom above the bedroom, or a bathroom above the main entry. In each of these cases you would have to constantly keep an eye on the energy of your bathroom in order to keep the overall energy of your home fresh, stable and harmonious.
With any bathroom location, it is mostly a matter of keeping its energy clean and clutter-free, as well as balancing the feng shui elements right. Of course, keeping the bathroom door closed at all times is a classical feng shui tip!
Bathrooms do have a predominant Water feng shui element energy, and, yes, the Water feng shui element weakens the Metal feng shui element. Knowing that, you will just have to make an effort and be conscious of strengthening the Metal feng shui energy and weakening the Water feng shui energy for a bathroom in the West or Northwest.
How do you do that? Earth feng shui element will help you the most, as Earth strengthens Metal and weakens Water in the relationship of the five feng shui elements.
So, go for Earth and Metal feng shui colors in your West or Northwest bathroom (for example, light yellow or sandy colors for Earth or white and gray colors for Metal). Definitely limit the Water feng shui element colors, which are blue and black colors.
Also try to limit a strong presence of mirrors, as mirrors bring the Water feng shui energy.
Focus on creating a powerful presence of the needed feng shui elements in a subtle and harmonious decor scheme for your bathroom, and you are sure to remedy a potentially challenging feng shui bathroom location.