Under California's loitering laws, Penal Code Section 555.2, a person may not loiter "in the immediate vicinity of a posted property." The statute does not prohibit peaceful picketing at the site of a labor dispute.
Definition of Loitering
California Penal Code Section 653.20(c) and Health & Safety Code Section 11530(a) define loitering as a "means to delay or linger without a lawful purpose for being on the property and for the purpose of committing a crime as opportunity may be discovered."
General Loitering Laws
Penal Code Sections 552 through 555.5 prohibit loitering at or near property that is posted with a sign that reads "trespassing-loitering forbidden by law" or a sign describing the lawful purpose for being near the property followed by the words "no trespassing." Whether a person is loitering as defined is determined from the totality of the circumstances. Violation of California's loitering laws constitutes a misdemeanor.
Loitering for the purpose of soliciting or engaging in prostitution is prohibited by California Penal Code Sections 653.20 through 653.28.
Loitering: Commonly Known Drug Areas
Loitering in a public place "manifesting the purpose and with the intent to commit" a drug-related offense is also prohibited by California Health & Safety Code Section 11532.