California Code, Government Code - GOV § 65906

Variances from the terms of the zoning ordinances shall be granted only when, because of special circumstances applicable to the property, including size, shape, topography, location or surroundings, the strict application of the zoning ordinance deprives such property of privileges enjoyed by other property in the vicinity and under identical zoning classification.

Any variance granted shall be subject to such conditions as will assure that the adjustment thereby authorized shall not constitute a grant of special privileges inconsistent with the limitations upon other properties in the vicinity and zone in which such property is situated.

A variance shall not be granted for a parcel of property which authorizes a use or activity which is not otherwise expressly authorized by the zone regulation governing the parcel of property. The provisions of this section shall not apply to conditional use permits.