Each rehab center will have its own policy, so it’s best to check ahead of time to see if cellphones are allowed at any particular rehab.
Many rehab centers require a 7-day “blackout” period where the patient will not be allowed to have contact with friends and family outside of the facility. This blackout is designed to help that person focus on detox and adjust to their new surroundings, as well as to eliminate any immediate threats to their emotional well-being.