Except as provided in section 13, reimbursement for the excise imposed under this chapter shall be paid by the occupant of any such room to the operator and each operator shall add to the rent and collect from the occupant the full amount of the excise imposed by this chapter or an amount equal as nearly as possible or practical to the average equivalent thereof and such excise shall be a debt from the occupant to the operator when so added to the rent and shall be recoverable at law in the same manner as other debts.
Mass. Gen. Laws ch. 64G, § 4