Except for debt to fund that part of any project that has been approved for grant financing by the State Government or Federal Government to meet the requirements of the United States Clean Water Act and the Maine Revised Statutes, Title 38, chapter 12, including any related facilities not eligible for that financing but essential to the operation of the approved project as an integral system, for debts in excess of the amount specified in this section, the following petition and referendum procedure applies. If, on or before the 7th day following the date of the special district meeting, a petition signed by at least 5%, but not fewer than 50, of the registered voters of the district is filed with the clerk of the district requesting reference of the vote of the trustees to referendum, the clerk of the district shall call and hold a special election of the voters of the district for the purpose of submitting to referendum vote a question of approving the vote of the trustees. The vote of the trustees is suspended until it has received approval by vote of a majority of the voters of the district voting on the question at the special election.

Sec. 17. Rates. All persons, firms and corporations, whether public, private or municipal, shall pay to the treasurer of the district the rates, tolls, rents, entrance charges, impact fees and other lawful charges established by the trustees for the sewer or drainage service used or available with respect to their real estate. The rates include rates for the district's readiness to serve charged owners of real estate abutting on or accessible to sewers or drains of the district but not actually connected to the district, whether or not such real estate is improved. For the purposes of this Act, "other lawful charges" and "other charges" include interest on delinquent accounts at a rate not to exceed the highest lawful rate set by the Treasurer of State for municipal taxes.

Rates, tolls, rents, impact fees and entrance charges must be uniform within the district when both the cost to the district of installation and maintenance of sewers or their appurtenances and the cost of service are substantially uniform. Nothing precludes the district from establishing a rate, toll, rent, impact fee or entrance charge higher than the regular rates, tolls, rents, impact fees and entrance charges in sections where, for any reason, the cost to the district of construction and maintenance, or the cost of service, exceeds the average. The