Except as may be required by chapter 15.3 of Title 46, the district and all its revenues, income and real and personal property shall be exempt from taxation and from betterments and special assessments and the district shall not be required to pay any tax, excise or assessment to or for the state or any of its political subdivisions; provided, however, that the district is authorized to enter into agreements to make annual payments in lieu of taxes with respect to property of the district located outside the town. Bonds and notes issued by the district and their transfer and the income therefrom, including any profit made on the sale or exchange thereof, shall at all times be exempt from taxation by the state and all political subdivisions of the state. The district shall not be required to pay any transfer tax of any kind on account of instruments recorded by it or on its behalf.