How can a bath addict become more environmentally friendly?

I really want to be more green. I recycle and turn off lights when I am not using them. Overall, I would say my carbon footprint is lower than the average. However, I love soaking in the bathtub after a long day or when I have a cold. This makes me feel guilty though, as it uses more water than a shower. I would say I take a bath probably twice a week and shower the other days. Show I feel this guilty? It's my biggest environmental vice.