I will try to best answer your question.
After reading your post, I believe your question is whether you can leave the state when there is a DHS case pending but no determination reached by juvenile court regarding delinquency. In order to answer this question I will have to make certain assumptions, if any of my assumptions are incorrect please advise me of the same so that I can tell you whether that will change my response.
Since DHS is involved I am assuming that there is a safety plan in effect. I'm also assuming that you still have your children placed with you under this safety plan. If your children are not placed with you that means that there is an order of an emergency nature and they have placed the children under some sort of temporary custody arrangement. If there is an order placing the children in someone else's custody, even if it is a temporary order, you will be in violation of the same and you will not be allowed to leave the state.
If there is no safety plan and custody remains with you you may seek treatment inside or outside the state as long as there is no order requiring the children to remain in the state. I would strongly suggest if possible seeking treatment in the state rather than out of the state. By trying to leave the state it will appear as though you are fleeing rather than addressing the actual issue.
Even if you leave the general area, but remain in the state, that would require a new defax office from a different county to potentially be involved. If you are returning to family outside the state and can place the children with family temporarily while you receive treatment that would be your best option. Then the children will be outside any potential risk from your addiction and we give you the best argument to DHS as to why you left. If your family is in the state I would go to your family in the state as opposed to leaving the state. By addressing the two major concerns, you are removing the need for the States involvement.
I tried to give you a couple different options depending on your exact scenario. Dealing with DHS can be difficult with a good case worker, in a nightmare if you have a bad case worker. I still think and recommend that place in your children with family members that would put it in the savings environment would help prevent and remove the need for DHS to make a placement. Simultaneously you would need to enroll yourself into a treatment program in order to address any addiction issues.