Cal. Business and Professions Code § 16002.2

No city shall impose a license fee or tax, other than a fee or tax based on gross receipts, for the privilege of renting, leasing, or operating laundry equipment, whether or not coin operated, upon any individual or firm whose business is limited exclusively to renting, leasing, or operating such equipment, which license fee taxes or has the effect of taxing any gross receipts, other than gross receipts actually derived from the conduct of business within such city. For purposes of this section, the tax shall be based on the entire gross receipts of the taxpayer derived within the city, and no minimum tax shall be imposed upon any business location, nor shall such tax be measured by the number of business locations or machines of the taxpayer within the city. This section shall not apply to coin-operated laundry equipment owned and operated by a retail establishment providing coin-operated laundry equipment for general public use.