Rockland County, NY Environmental Rules: Flood Zones (2026)

Section 353-4 makes it a breach of the chapter for any person or firm to undermine stream bank stability, fill or dump material that obstructs flow, impair channel integrity, build or develop in a way that adversely affects flow, locate structures or obstructions, alter drainage or absorption patterns, or excavate, all within the one-hundred-year floodplain of a designated County stream or water recharge area. The Rockland County Drainage Agency implements and enforces the chapter and is directed to "aggressively pursue" a policy against development, construction or encroachment in the floodplain or a water recharge area.

Section 353-3 defines the one-hundred-year floodplain as the area submerged by a flood with a one-percent annual chance of occurring, plus an additional 100 feet from the frequency line the Drainage Agency has studied; if no study exists yet, the floodplain line defaults to 150 feet from the stream's center line or three feet in elevation above the normal high-water line, whichever is greater. D lets the Drainage Agency or County Attorney seek permanent or temporary easements from floodplain property owners barring new structures, obstructions, drainage alterations, excavation or channel changes, and requiring the owner to allow Agency personnel to enter for inspection and maintenance after notice.

A property owner may apply to the Drainage Agency under § 353-5 for a written waiver of the chapter's restrictions; the request must be posted at the County Clerk's office, published in the official County newspaper and posted within 300 yards of the work site at least 15 days before a hearing, and the burden is on the applicant to show the waiver would not defeat the chapter's intent. A denied or granted waiver can be challenged in Rockland County Supreme Court under Article 78.