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122,089 NYC properties are eligible for accessory dwelling units. Check yours free in 30 seconds.
Go from eligibility check to construction start — we guide you the entire way.
Enter your address and get an instant result based on zoning, lot size, and building class.
Browse HPD pre-approved designs — skip months of architectural review and permitting.
Connect with verified contractors, secure financing, and start construction.
HPD-approved designs ready to build — skip months of architectural review.
Costs vary by ADU type, site conditions, and finishes. Here are typical ranges for NYC.
$100K – $250K
Convert an existing cellar or basement into a legal dwelling unit.
$150K – $300K
Transform a detached garage into a fully habitable accessory unit.
$250K – $400K+
Ground-up construction of a new detached dwelling in your yard.
The City of New York's Plus One ADU Program provides forgivable loans and grants to eligible homeowners building accessory dwelling units. Cover most or all of your construction costs.
Everything homeowners need to know about NYC ADUs.
Use our free eligibility checker — enter your address and we cross-reference zoning, lot size, building class, and other NYC regulations to give you an instant answer.
NYC allows three main types: basement/cellar conversions, garage conversions, and new detached backyard cottages (up to 800 sqft). Your lot determines which options are available.
Costs range from $100K for a basement conversion to $400K+ for a new cottage. The NYC Plus One program offers up to $395K in financing to offset these costs.
Yes. Under the City of Yes program, the property owner must occupy either the primary residence or the ADU. This is an owner-occupancy requirement.
Using an HPD pre-approved plan can cut the permitting timeline significantly — from 6–12 months down to as little as 2–4 months, since architectural review is already complete.
It takes 30 seconds. Find out if you can build an ADU and how much it could be worth.