Nash County, NC Environmental Rules: Stormwater Management (2026)

Section 12-3.2 of the Unified Development Ordinance (Appendix A) applies throughout the planning jurisdiction, meaning every parcel in unincorporated Nash County outside a municipality's limits. A development's drainage system must prevent undue retention of surface water unless the pooling comes from an approved sedimentation or stormwater control device, or simply matches the site's pre-development drainage pattern. Surface water can never be channeled into a sanitary sewer line. Wherever practicable, a development's drainage system must tie into the drainage systems on surrounding roads and properties. Section 12-3.2(D) puts the burden both ways: a development cannot impede natural flow from higher adjacent land in a way that damages those upslope properties, and it cannot collect and channel water onto lower parcels at volumes or locations that cause substantial damage downhill.

Parcels inside the Tar-Pamlico River Basin Overlay District face an added layer of permitting under Section 12-3.3: any activity disturbing more than one acre for a new single-family or duplex development, or more than half an acre for multifamily, commercial, industrial or institutional work, needs a stormwater permit from the Stormwater Administrator before land-disturbing work begins. That permit enforces nitrogen loading capped at 4.0 pounds per acre per year and phosphorus capped at 0.4 pounds per acre per year, and requires the project to avoid increasing peak flow leaving the site during a one-year, 24-hour storm. The Stormwater Administrator reviews and approves, conditions or denies applications within ten working days, and permits expire after six months if construction has not started.