Amends GS 153A-277(a1), GS 160A-314(a1), and GS 162A-9 to authorize cities, counties, and water and sewer authorities to provide customers with credits against stormwater fees if the property has a green roof (as defined in amended GS 143-138). The provisions define how to calculate the credit and place an upper limit on the amount of the credit. Enacts new GS 105-277.18 to the tax code to define the term green roof (definitions identical) and provide that qualifying green roof improvements are considered a special class of property under Article V, Sec. 2(2), of the NC Constitution. Owners of property with qualifying green roof improvements are entitled to a partial exclusion of 10% of the improvement’s appraised value during the first five taxable years after the completion of the improvement. Amends GS 143-138 to define the term green roof and direct the Building Code Council to include provisions in the Building Code pertaining to green roof technologies. Enacts new GS 153A-327 directing urban counties (those that rank in the top 10 for population) to adopt guidelines addressing installation of green roofs (as defined in amended GS 143-138). Effective July 1, 2011; tax code changes apply to improvements made on or after that date.