People often ask how long they can hold someone in jail for a probation violation in Wisconsin. These types of probation holds are commonly referred to as VOP holds, or PO holds. (The two terms are interchangeable.) Although Wisconsin has administrative rules that set time limits for how long they can hold someone in jail on a PO hold, these time limits are not firm and can be extended with very little effort by the probation agent, which means a person may end up sitting in jail for months on a VOP hold.