California Code, Welfare and Institutions Code - WIC § 729.9

If a minor is found to be a person described in Section 602 by reason of the commission of an offense involving the unlawful possession, use, sale, or other furnishing of a controlled substance, as defined in Chapter 2 (commencing with Section 11053) of Division 10 of the Health and Safety Code, and, unless it makes a finding that this condition would not serve the interests of justice, the court, when recommended by the probation officer, shall require, as a condition of probation, in addition to any other disposition authorized by law, that the minor shall not use or be under the influence of any controlled substance and shall submit to drug and substance abuse testing as directed by the probation officer.