Ill. Admin. Code tit. 86 § 696.101
Under the Municipal Motor Fuel Tax Law [65 ILCS 5/8-11 -2.3] (Law), in addition to any other tax that may be imposed, a municipality in a county with a population of over 3,000,000 inhabitants may also impose, by ordinance, a tax upon all persons engaged in the municipality in the business of selling motor fuel, as defined in the Motor Fuel Tax Law [35 ILCS 505], at retail for the operation of motor vehicles upon public highways or for the operation of recreational watercraft upon waterways. The tax may be imposed, in one cent increments, at a rate not to exceed $0.03 per gallon of motor fuel sold at retail within the municipality for the purpose of use or consumption and not for the purpose of resale. The tax may not be imposed under this Section on aviation fuel, as defined in Section 3 of the Retailers' Occupation Tax Act [35 ILCS 120]. The Municipal Motor Fuel Tax imposed under the Municipal Motor Fuel Tax Law is an occupation tax upon retailers of motor fuel and is administered by the Illinois Department of Revenue (Department) in the same manner as the Retailers' Occupation Tax. The tax imposed by a municipality under the Municipal Motor Fuel Tax Law and this Part, and all civil penalties that may be assessed as an incident of the Law and this Part, shall be collected and enforced by the Department. A municipality, only part of which is located in a county with a population of over 3,000,000 inhabitants, qualifies as a municipality in a county with a population of over 3,000,000 inhabitants and is therefore authorized to impose the tax under the Law and this Part. If, however, such a municipality imposes a tax under the Law and this Part, the tax must be imposed upon all persons engaged in the municipality in the business of selling motor fuel, in accordance with the Law, and not only those persons engaged in the business of selling motor fuel in the portion of the municipality located in a county with a population of over 3,000,000 inhabitants.
The legal incidence of the Municipal Motor Fuel Tax Law is on the seller. The General Assembly has authorized persons subject to any tax imposed pursuant to the authority granted in the Law to reimburse themselves for their Municipal Motor Fuel Tax liability by separately stating that tax as an additional charge. The charge may be stated in combination, in a single amount, with State tax that sellers are required to collect under the Use Tax Act [35 ILCS 105], pursuant to such bracket schedules as the Department has prescribed (see 86 Ill. Adm. Code 150.Table A). [65 ILCS 5/8-11 -2.3]
Any amount added to the selling price of motor fuel by the seller because of a Municipal Motor Fuel Tax shall not be regarded as a part of the seller's gross receipts that are subject to Illinois Retailers' Occupation Tax or any local occupation tax administered by the Department.
Ill. Admin. Code tit. 86, § 696.101