Is there a statewide ADU mandate in New York?

No. As of September 11, 2025, ADU legality and standards are set by local governments. State programs support ADUs, but do not create a universal mandate. Verify locally.

What state support exists?

The Plus One ADU program (NYS HCR) funds creation or legalization of ADUs through local partners. Counties may also adopt a property tax exemption for ADU value increases under RPTL 421-p*2.

What’s the status in NYC?

City of Yes allows ADUs on many one- and two-family lots, but DOB Bulletin 2025-006 clarifies approvals depend on DEP flood maps and DOB rules being in effect.

Are there ADU tax breaks?

Some counties (e.g., Albany, Ulster) adopted local ADU tax exemptions enabled by state law (caps and terms apply; STRs may be excluded).

Do I need parking or owner-occupancy?

Those are local decisions. Check your city/town code and any HOA rules.

New York State ADU Rules & Programs

Name: New York ADU planning — short walkthrough
Uploaded: 2025-09-11
Duration: 2 min 30 s
Description: A quick video overview of the steps to plan an ADU under local control in New York.

New York has no universal ADU mandate. This page shows how to check your local ordinance, use state programs like Plus One grants, see county ADU tax breaks, and understand NYC’s status—plus official links.

Find ADU builders Get a cost estimate See permit steps

TL;DR: No statewide ADU mandate in New York as of Sept 11, 2025—rules are local. The state’s Plus One ADU program helps fund ADUs via partners, and some counties offer ADU tax exemptions under RPTL 421-p*2. In NYC, City of Yes allows ADUs, but approvals depend on flood and DOB rules. {{verify locally}}

Local control Plus One grants County tax exemptions NYC: contingent approvals

Illustrative ADU behind a New York single-family home

On this page

New York ADU — at-a-glance

Statewide status

No universal ADU mandate; local ordinances govern. {{verify locally}}

State funding

Plus One ADU (NYS HCR) via local partners; cycles open/close.

Tax incentives

Counties may adopt ADU exemptions under RPTL 421-p*2 (e.g., caps up to $200k; STRs often excluded).

NYC status

ADUs allowed under City of Yes; approvals contingent on flood/DOB rules per DOB Bulletin 2025-006.

Parking/owner-occ

Set locally; confirm your town code and HOA rules.

Process

Apply with your local building department (DOB NOW in NYC).

Program and exemption availability varies by county and municipality; always verify current eligibility and terms. {{verify locally}}

How to plan an ADU in New York (5 steps)

Confirm local allowance: Check your city/town/village code; verify overlays (historic, flood, coastal). {{verify locally}}
Safety & flood: Plan two means of egress, compliant ceiling heights, and flood-resilient design.
Explore Plus One: Review HCR’s Plus One ADU program and local partner availability; check income/owner-occupancy criteria.
Check county tax break: See if your county adopted the RPTL 421-p*2 ADU exemption and its conditions (e.g., STR exclusions).
Apply & build: File with your local building department (NYC: DOB NOW). Upload searchable PDFs; respond to objections; pull permits; inspections; sign-off/CO.

Match with a builder Explore financing Estimate costs NYC specifics

Submittal checklist (quick scan)

Site plan + zoning diagram; flood exhibits if applicable
Floor plans & elevations; egress diagrams
Structural notes/calcs; energy compliance
Program documents (Plus One) if applying
County exemption application (if adopted)

Name files like ADU_NewYork_Plans_2025-09-11.pdf.

Size & program overview (illustrative)

Program landscape

Illustrative only. Funding cycles and local rules change. {{verify locally}}

County tax exemptions

Examples: Albany County (adopted), Ulster County (adopted/amended). {{verify locally}}

Local voice prompt

Try speaking to your assistant:

“Hey Siri, ask ADUPlanet — can I build an ADU at my address in New York?”

Follow-ups: “Is Plus One open?” “Do I qualify for a county tax exemption?” “What’s my flood status?”

Community rating (pilot)

Be the first to rate this guide

Official links (verify here first)

FAQ — New York State ADUs

Is there a statewide ADU law?

No. Local governments control ADU allowances. State programs support ADUs, but they don’t mandate them statewide. {{verify locally}}

What is Plus One?

A state program (via NYS HCR) that funds ADUs through local partners; funding waves open/close and eligibility applies. See the program manual. {{verify locally}}

Can I get a tax break?

Some counties adopt an ADU exemption enabled by RPTL 421-p*2, often capping exempted value and excluding STR use. Check your county’s law. {{verify locally}}

How does NYC handle ADUs?

NYC allows ADUs under City of Yes, but approvals are contingent on flood and DOB rules (see DOB Bulletin 2025-006). {{verify locally}}

Where should I start?

Check your local code; then explore Plus One, county exemptions, and our NYC guide if you’re in the five boroughs.

2-minute planning walkthrough (New York)

Transcript (abridged): Step 1 — Check local ordinance; Step 2 — Safety & flood; Step 3 — Explore Plus One; Step 4 — Check county tax break; Step 5 — Apply & build. {{verify locally}}