You must file a Petition for Modification and special relief to have the visits terminated based upon the impact they have on the child. Grandparents are only allowed visitation if it is in the best interest of the child and it doesn't interfere with the parent/child relationship. I would contact/retain an attorney to discuss this matter in more detail, as this request requires a hearing and determination by the Court.
I agree with Attorney Vandergrift that you can file a Petition to terminate the visits. However, you will need to meet with an attorney because it will be very difficult for you to handle this matter on your own. I would suggest that you contact the legal aid office in your county and the bar association to determine whether there are attorneys who will assist you either free of charge or at a reduced fee. Because of your age, you may be able to qualify. You should write down your concerns and bring any evidence that you have concerning the drug use of the person living in the household with you to the lawyer's office.
My response is based solely on the limited information contained in the question. It is not meant to substitute your attorney's advice.
I agree with my colleagues. if you are unhappy with the present order and believe that it is no longer in the best interest of your child, you should file a Petition for modification with the Court.
You should consult with an experienced attorney who can help you file the appropriate petition to modify the custody order. If people living in the child's home have a history of certain enumerated offenses, like drug convictions, you can request a special hearing for the court to consider whether that person poses a risk of harm to the child as a result of thier criminal history.
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