Section 4A. A water company that has, prior to the effective date of this section, entered into or shall thereafter enter into any contract with an affiliated company as herein defined, for the payment of any fees, salaries, commissions or percentages for services of any kind furnished or rendered, or to be furnished or rendered, to such water company shall file with the department within ten days after said effective date a copy of any such existing contract and any extension or modification thereof, if in writing, or, if not in writing, a statement of all the terms thereof, and within ten days after the execution of any such contract, or of any extension or modification of any such contract whether or not existing on said effective date, a copy thereof, if in writing, or, if not in writing, a statement setting forth all the terms thereof. The words ''affiliated company'', as appearing in this section, shall be defined as in section eighty-five of chapter one hundred and sixty-four except that, in construing the definition in said section eighty-five for the purposes hereof, the words ''a company subject to this chapter'' shall mean a company as defined in section one of this chapter. A water company failing to file a copy or statement as required herein shall forfeit five dollars for each day during which such failure continues. All such forfeitures may be recovered by an information in equity brought in the supreme judicial court by the attorney general, at the relation of the department, and when so recovered shall be paid to the commonwealth.