1,104. Being Supported by Another Woman

161:12 Another woman may not support the one who is immersing because the water won't reach the place where she is holding her. In an extenuating case of need, the friend should first immerse her hands in the mikvah and then hold the one immersing. She may not do so with a tight grip buy with a regular grip, like a person normally does.

161:13 Where possible, one should not immerse in a mikvah where there's mud on the bottom because it may create a chatzitzah. In compelling circumstances, the practice is to be lenient because the mud in the water isn't so thick. However, mud on the bank of a river, which sticks to one's feet, is a chatzitzah. Therefore, when entering a river to immerse, a woman must be careful to clean her feet thoroughly of the mud that stuck to her from the river bank. If she wants to put something to stand on in the river where her feet will be while immersing, she must consult an authority because there are many things that one may not stand on while immersing.