I live in Iowa and my 17 year old daughter no longer lives with mom. When does child support end? She has not lived with her for some time now>

Where and under what conditions is she living apart from the mother? If she is playing house with some boyfriend then go to court to seek a modification. A judge will rule if it can be stopped or not.

It will continue till you get the child support order stopped.

Why is the 17 not living at home, they can not just move out, if the mother is not properly supervising child, you can move for custody and ask support from mom