New York City does not have a general-purpose ADU ordinance. Most accessory dwelling units, including basement and cellar apartments, remain illegal under the NYC Zoning Resolution and NYC Building Code, except under the Local Law 22 of 2024 basement and cellar conversion pilot in specific community districts.
The NYC Zoning Resolution generally prohibits creation of new dwelling units in one- and two-family homes beyond the existing certificate of occupancy. Cellar apartments are not legal under NYC Building Code, and basement units must meet light, air, ceiling-height, and egress standards in MDL Section 34. Local Law 22 of 2024 created a basement and cellar legalization pilot for owner-occupied one- and two-family homes in 15 designated community districts. Outside the pilot, the only legal accessory units are pre-existing legal multi-family Certificates of Occupancy. DOB requires Alteration Type 1 filing for any change in unit count, with a Professional Engineer or Registered Architect.
Unpermitted ADUs and illegal basement units trigger DOB Class 1 or 2 violations, vacate orders under MDL Section 309, and ECB fines up to $25,000. HPD can issue Class C violations and refer matters to the City Sheriff.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
New York, NY
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New York, NY
Under Admin. Code Sec. 24-235, an animal owner may not permit unreasonable animal noise that is plainly audible inside any nearby residential property for 10...
New York, NY
Under Admin. Code Sec. 24-222, construction work is unlawful except on weekdays between 7:00 a.m. and 6:00 p.m. Limited weekend work (Sat/Sun 10 a.m.-4 p.m.)...
New York, NY
Under Admin. Code Sec. 24-231, music from a commercial establishment may not exceed 42 dB(A) measured inside any nearby residential dwelling unit, nor 45 dB ...
New York, NY
New York City has no blanket 'quiet hours' curfew, but the Noise Code's general prohibition (Admin. Code Sec. 24-218) makes it unlawful to make any unreasona...
New York, NY
New York City bars street storage of boat trailers, mobile homes, and mobile medical diagnostic vehicles: under 34 RCNY 4-08(m)(8) none may be parked on any ...
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