Enacts new GS 47F-3-123 to prohibit the regulation or ban of water efficiency or energy efficiency improvements by homeowners associations. Provides the following exemptions from the prohibition: (1) for declarations of covenants registered before October 1, 2011, the covenant prohibits the specific water or energy efficiency improvement installed or proposed by the property owner or (2) for covenants registered on or after October 1, 2011, the restriction lists the specific water and energy efficiency measures that are prohibited, and the improvement installed or proposed by the property owner is substantially the same as a restricted measure. Defines water efficiency improvement and energy efficiency improvement. Effective October 1, 2011.