What steps can we take if we suspect the non-custodial parent of drug use?

This is not the kind of question that lends itself to a good answer through this forum. Much more information is needed, which includes what the visitation terms are in existing orders, what visitation is anticipated, how old the child is, how long the visits will be, what drugs the other parent is supposedly using and what proof is available, and more. Your best option is going to be pulling together all of your paperwork and evidence and sitting down for an in-person consultation with an attorney who practices before the Court your case is in.

I agree with Ms. Whitbeck and will add that you need some pretty concrete evidence before the court will take you very seriously. For example, did CPS remove the child or has she had a recent DUI charge? Did she admit to drug use or tell you she's going to go the hospital for 90 days? Is there something more than a gut feeling? The court won't do anything unless you can prove that there is a direct link between any drug use (legal or not) and her inability to parent. Without that, nothing will happen.