One of the most important parts of the City of Yes ADU proposal is the size limit for new accessory units. The framework uses an 800 square foot maximum to keep ADUs small, safe and consistent across residential neighborhoods.

What the 800 Square Foot Rule Means

According to draft text from the NYC Department of City Planning (2024):

• A new ADU can be up to 800 square feet of floor area.

• This applies to detached units, garage conversions and some basement ADUs.

• Units must still meet all building code requirements for height, egress and fire safety.

• The limit is intended to preserve scale in low density neighborhoods.

What You Can Fit in 800 Square Feet

Most ADUs of this size comfortably allow:

• A one bedroom layout

• Full bathroom

• Kitchen or kitchenette

• Open living area

• Storage and mechanical space

Attached garages and many detached garages in Staten Island already fall near this footprint, making conversion simpler.

Why Staten Island Benefits Most

Neighborhoods in R1 to R3 zoning have the space and lot depth for detached ADUs within the 800 square foot cap. Brooklyn homeowners may see more benefit through garage conversions rather than new structures.

What Homeowners Should Verify

• Lot coverage percentage

• Rear yard depth

• Fire separation requirements

• Whether your ADU is attached or detached

• Any flood zone restrictions

For many homeowners, the 800 square foot rule is the difference between an ADU that fits the lot and one that requires redesign.

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Joseph Ranola | Five-Star Staten Island & South Brooklyn Realtor® (30 + Google reviews)
Associate Broker · Matias Real Estate | Founder · Bridge & Boro Team
Serving 103xx and 11209 / 11214 / 11228 | $25 M + closed volume
📞 917-716-1496 | ranolarealestate.com