Conn. Gen. Stat. § 46b-141d: Credit for presentence detention.

Any child who is arrested and held in a juvenile residential center, an alternative residential center or a police station or courthouse lockup prior to the disposition of a juvenile matter shall, if subsequently adjudicated as delinquent by the Superior Court and sentenced to a period of probation supervision or probation supervision with residential placement, earn a reduction of such child's period of probation supervision or probation supervision with residential placement, including any extensions thereof, equal to the number of days that such child spent in such residential center or lockup.