Zoning Overlays & Bonuses in Islip, NY

If you live in Islip or are thinking about moving there, zoning overlays & bonuses are one of those things you probably won't think about until they affect you directly. Islip has 2 specific rules on the books covering different aspects of zoning overlays & bonuses, and some of them might surprise you.

Density Bonus Law

The Town Board may grant added density above the base caps of nine units/acre for apartment houses, six for attached single-family homes and four for detached homes in Residence CA-tier districts. Bonuses reward on-site affordable units or renewable-energy/LEED design, follow a public hearing, and can never push density past 12 or 10 units/acre respectively.

Key details: Base density (apartments): 9 units/acre. Base density (attached single-family): 6 units/acre. Absolute cap with bonuses: 12 units/acre apartments, 10 attached. Affordable-housing bonus threshold: 20% of units affordable on site. Max renewable-energy bonus: 3 units/acre at 70%+ renewable energy.

Bonus density is conditional, not automatic: § 68-173.3A(2) bars construction of the bonus unit(s) until the Commissioner of Planning and Development has verified LEED/NGBS certification, and § 68-173.1C requires Town Board approval through the Department of Planning and Development's Article IVA process before any bonus is used. A project that builds bonus units without completing that approval and certification chain is over its permitted base density and subject to the Town's standard zoning enforcement and building-permit denial.

Downtown Design Guide

Islip's Downtown Development District (DDD), created to revive the Town's hamlet centers like Bay Shore, gives the Planning Division real design authority. Section 68-180.9 lets it demand extra architectural elements such as front porches and decorative windows and requires its sign-off on the design and materials of every element of a DDD building.

Key details: District name: Downtown Development District (DDD). First mapped area: Downtown Bay Shore. Design authority: Planning Division approves materials/elements. Structure changes: Need Planning Division or site plan approval. Parking rule: Under-building parking must be screened.

Altering or demolishing a structure inside a mapped Downtown Development District without Planning Division approval, or ignoring its architectural or parking-screening conditions, is enforced as a Chapter 68 zoning violation under § 68-421: up to $2,000 in fines, up to 15 days' imprisonment, or both, with each day of continued noncompliance a separate offense.

This is not one of those rules that cities tend to ignore. Islip actively enforces its downtown design guide requirements.

The Bottom Line

Islip's zoning overlays & bonuses rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Islip is broadly strict or permissive.

This guide is based on Islip's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.