N.C. Gen. Stat. § 153A-193.1

The board of commissioners is authorized to establish a schedule of discounts to be applied to assessments paid before the expiration of 30 days from the date that notice is published of confirmation of the assessment roll pursuant to G.S. 153A-196. Such a schedule of discounts may be established even though it was not included among the terms of payment as specified in the preliminary assessment resolution or final assessment resolution. The amount of any discount may not exceed thirty percent (30%).