I do try to limit the chemicals I put onto my body (no sulfates or parabens in my soaps, shampoos, or lotions, natural toothpaste, and I'm trying to switch over to more natural makeups), but I still participate in daily hygiene rituals. I'll admit that I don't shampoo my hair daily, in fact, 99% of the time I wash it with conditioner instead of shampoo, and that's only every 2nd or 3rd day, with a plain water rinse in between. For my hair type, this routine maximizes the curl and minimizes the frizz, while still flushing out the grime. And I don't wear deodorant/antiperspirant on a daily basis because I've found that I don't produce odiferous sweat except when I exercise, and when I exercise I shower immediately afterwards anyhow. I can't come up with any justification for omitting teeth cleansing though.
I have decided to save water by showering at the gym. I don't take every shower there, but if I'm going to go workout I might as well use their water instead of mine, even if I'm coming straight home afterwards. And I try to get to the gym 5-6 times a week. This is my first month at my new gym, with locker rooms nice enough that I'm willing to shower there, so it remains to be seen if it actually makes an appreciable difference in our water bill.