Thank you for reaching out to us.

Loose hairs found on the body after cleaning and combing for mikveh typically cover only a tiny area of the body, and women are usually not particular about them. Therefore, they are not considered a chatzitzah.

However, it is customary to remove even small items about which a woman is not particular prior to immersion (Rema, Yoreh De'ah 198:1). Loose hairs are a bit of a special case, though. They can be very pesky to pick off. More important, they typically do not actually wind up blocking the water from the body, bacause they float off in the water. (Hair is less dense than water, so it floats, and the water reduces friction and creates drag, separating loose hairs from the skin to start with.)

In practice, if a woman combs through her hair, we trust that any loose hairs have been removed from her head or will float off when she immerses. Repeated combings for this purpose are not recommended, as they are liable to generate more loose hairs each time.

A woman performing iyun (visual inspection) should look out for clumps of hair on her skin and should remove those and any hairs on her skin that actually bother her. This is also a courtesy to women immersing after her, who will not want to find a lot of hair in the mikveh water. But a woman does not need to seek out and remove single loose hairs that she wouldn't usually notice, nor does she need to ask the mikveh attendant to do so.

After immersion, a loose hair found on the body can be assumed to have floated onto the body in the mikveh water or to have gotten there from the towel, and does not invalidate immersion.

Please let us know if we can be of further assistance.