North Hempstead, NY Environmental Rules: Stormwater Management (2026)

Chapter 46A's stated purpose, in § 46A-2, is to meet the SPDES General Permit for Municipal Separate Storm Sewer Systems and the SPDES General Permit for Construction Activities, minimize increased runoff, flooding, streambank erosion and nonpoint source pollution from development. Section 46A-8A treats designs built to the New York State Stormwater Management Design Manual and the New York Erosion Control Manual as presumptively compliant, while § 46A-8B sets the water-quality floor: no land development activity may cause a turbidity increase producing substantial visible contrast to natural conditions in State waters.

Beyond erosion controls, § 46A-7B(2) requires post-construction water quantity and quality controls whenever a project discharges to an impaired or TMDL-designated water, disturbs five or more acres, or disturbs between one and five acres outside single-family homes and farms; those plans must include hydrologic and hydraulic analysis, a comparison of pre- and post-development runoff, and a maintenance schedule with recorded easements under § 46A-7B(3). Once a stormwater management practice is built, § 46A-9C makes the owner or operator responsible for a preventive and corrective maintenance program with written procedures and trained personnel, and discharges cannot exceed design criteria or violate the § 46A-8B water-quality standard.

The Town Board must approve a formal, recorded maintenance agreement before final plan approval under § 46A-9D, or may instead accept dedication of the facility, and the Town can charge fees at prevailing rates for SWPPP review, inspections and maintenance oversight under § 46A-13.