Well, I won't lie, the water does get a bit murky after a watebirth, mostly from vernix or bleeding after the baby is born. Most women pass a little bit of stool during the birth, but if this is something that concerns you, have a strainer or a little net on hand and give a support person strict instructions to discreetly remove it before you see it. In all honestly, although you feel self-conscious about it now, I suspect at the time you really won't notice, or care.