I delivered in my own bath at home, and the water was pretty much fine, until I delivered the placenta - then it got pretty murky! But since it was just the bath, we pulled the plug, and rinsed it out while I had a shower and DH snuggled with our new little girl. (Wow, just writing that makes me look forward to meeting this new little person.....) Then the midwives refilled the tub and I had an herbal bath to help heal the "scrapes" I got (nothing that needed stitching) and nursed DD in there with me. By the way, you are less likely to tear in a water birth.
All the best!