North Hempstead, NY Landscaping Rules: Rainwater Harvesting (2026)

2, added in 1998 and amended several times through 2021, requires any construction that increases impervious surface by more than 5% of the lot area or 750 square feet, whichever is less, to retain 2 1/2 inches of rainfall on site. Subsection B lists acceptable erosion control and stormwater retention methods during construction, including hay bales, swales, berms, contour modification, landscaping, silt fences, rain barrels and drywells, and lets the Building Inspector require a field inspection before construction starts. Subsection C addresses permanent stormwater management after construction is complete: new site development must provide permanent erosion control and stormwater containment, again using methods such as swales, berms, contour modification, landscaping, rain barrels and drywells, with the Building Commissioner authorized to require corrective site work if existing or proposed conditions fail to control erosion or contain stormwater.

2C(4) sets the specific rain barrel limit: no more than one rain barrel of up to 60 gallons may be connected to each roof leader to satisfy the retention requirement in Subsection A. Drainage and erosion control plans supporting any of these methods must be prepared by a professional engineer, registered architect or registered landscape architect and submitted with the building permit application, and drywell placement must follow Nassau County drainage standards, though lot-size relief down to 10 feet from the normal 20-foot separation is available with a licensed architect's or engineer's certification.