''Water company'', a company, as defined in section 1 of chapter 165 or a municipal utility or any other waterworks system owned, leased, maintained, operated, managed or controlled by any unit of local government under any general or special law, which company, utility or system supplies water to a landlord through metered measurement. Any landlord imposing charges on tenants or otherwise engaging in any activity permitted under this section shall not be deemed thereby to be functioning as a water company as defined herein or to be subject to any laws or regulations regulating any such company.