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

Sec. 32-401 requires a stormwater permit "for all development and redevelopment unless exempt pursuant to this division," reviewed by the stormwater administrator within 30 working days of a complete submittal, with a second 30-day review if the applicant revises and resubmits. Sec. 32-406 sets the numeric water-quality standard: nitrogen and phosphorus loads "shall not exceed the following unit-area mass loading rates: 2.2 and 0.33 pounds per acre per year for nitrogen and phosphorus, respectively," or, for redevelopment that increases built-upon area, a 40 percent nitrogen and 77 percent phosphorus reduction from existing conditions.

Sec. 32-408 adds the runoff-quantity rule: stormwater systems must be "designed to control and treat the runoff generated from all surfaces by one inch of rainfall," and the development cannot cause a net increase in peak flow leaving the site for the one-year, 24-hour storm. Sec. 32-409 lets a developer meet part of the nutrient standard on-site and offset the rest, with the required on-site reduction scaled to how much land is disturbed, from 30 percent on a half-acre single-family lot up to 50 percent on parcels over an acre, before an off-site offset payment to the state Ecosystem Enhancement Program becomes available.

Sec. 32-413 requires an annual maintenance inspection report on every engineered stormwater control, sealed by a professional engineer, surveyor, landscape architect or other qualified inspector, filed with the stormwater administrator every year after as-built certification.