N.C. Gen. Stat. § 162A-77
A district may assume all outstanding indebtedness of any political subdivision in the district lawfully incurred for paying all or any part of the cost of a sewerage system, subject to approval thereof by a majority of the qualified voters of the district voting at an election thereon. Any such election shall be called and held in accordance with the provisions of the Local Government Finance Act, insofar as the same may be made applicable, and the returns of such election shall be canvassed and a statement of the result thereof prepared, recorded and published as provided in the Local Government Finance Act. No right of action or defense founded upon the invalidity of the election shall be asserted nor shall the validity of the election be open to question in any court upon any ground whatever, except in an action or proceeding commenced within 30 days after the publication of such statement of result. In the event that any such indebtedness of a political subdivision is assumed by the district, there shall be annually levied and collected a tax ad valorem upon all the taxable property in the district sufficient to pay such assumed indebtedness and the interest thereon as the same become due and payable; provided, however, that such tax may be reduced by the amount of other moneys actually available for such purpose. Such tax shall be determined, levied and collected in the manner provided by G.S. 162A-71 and subject to the provisions of said section.
Nothing herein shall prevent any political subdivision from levying taxes to provide for the payment of its debt service requirements as to indebtedness incurred for paying all or any part of the cost of a sewerage system if such debt service requirements shall not have been otherwise provided for.
N.C. Gen. Stat. § 162A-77