My daughter who is 20 was sent to a collection agency for a hospital bill. She is under my husbands insurance since she was a student. My question to you is who is responsible for the bill my husband or my daughter and will this hurt her credit in the future or will it go against my husband and I.
Both. The debt is your daughter's because she is over eighteen. However, if your husband is a guarantor of the debt, as is likely since he is the policy owner, the hospital will likely report the debt against his credit also. Get the insurer to straighten the matter out and pay the bill.
See also: http://info.corbettlaw.net/lawguru.htm