Definitely a "natural" birther here too - the thought of epidural needles scared me WAY more than the thought of the pain of birthing.
I had a water birth with my second baby.(my third came too fast to barely even make it to the hospital and by number four i just wanted the alien OUT by any means possible).
The water birth was absolutely the most intense, empowering, amazing experience - probably of my life truly. I could feel every single cell of that little body being born from me - and to this day - i wonder if that's why she and I have such a weird crazy connection. i mean - I connect with all of my babies in their own ways - but with K2, it is very intense. Much like her birth was.
I would highly recommend seeking more information on how to make this happen if its something you would like to try. And if you end up only laboring in the water and pushing out of the tub - you will still have had a unique way to help relieve some of the pain.
good luck with your decision and I hope you can find a way to make it work for you!