Possession of a controlled substance is typically a misdemeanor offense in California. Under the law, if you possess a controlled substance (such as cocaine, heroin, or methamphetamines) without a valid prescription, then you can be charged with a crime. This is often referred to a simple possession.
Possession of a controlled substance is usually punished by imprisonment in county jail for up to one year and/or a fine of up to $1,000. A court may impose probation instead of jail time. In some cases, a person charged with simple possession may be eligible for a diversion program, which will allow them to serve their sentence in a treatment program rather than in jail. If you have certain prior convictions, then simple possession may be charged as a felony.