NYC Property Due Diligence: The Real Government Links List
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Quick answer: ACRIS covers deeds, mortgages, and liens, but it doesn’t touch building violations, illegal work, zoning limits, flood risk, or contamination history. For that you need a handful of other city and federal databases: DOB NOW for permits and violations, DOF’s Property Information Portal for taxes, ZoLa for zoning, the NYC Flood Hazard Mapper for flood zones, and a few more below. None of them are hidden; they’re just scattered across a dozen agency websites that don’t link to each other.
Why isn’t ACRIS enough on its own?
ACRIS answers one question well: who owns this property and what’s recorded against it. It won’t tell you if the basement apartment is legal, if the roof deck was ever permitted, or if the block is in a flood zone. Those facts are held by the Department of Buildings, the Department of City Planning, and FEMA, not the City Register.
A lot of buyers stop at ACRIS because it’s the site everyone’s heard of, and it does feel thorough when you’re staring at forty years of deed history. But a clean deed says nothing about whether the extra bedroom shown in the listing photos was ever filed with the city.
What government sources should you actually check?
Below is the working list. Each one answers a specific question, and you generally only need to go deep on the two or three that matter for the property you’re looking at. A prewar co-op doesn’t need a flood check; a Zone A house in the Rockaways needs little else.
| Source | What it tells you | When you need it |
|---|---|---|
| DOB NOW: Public Portal | Current permits, active job filings, open violations, and complaint history, searchable by address or BBL. Runs on seven search types, including address and Building Identification Number (BIN). | Any purchase. Check before you even schedule a walkthrough. |
| BIS (Building Information Search) | The older records DOB NOW hasn’t fully absorbed yet: pre-2010 certificates of occupancy, historical violations, older permit history. | Older buildings, or when DOB NOW’s records feel thin for a building’s age. |
| DOF Property Information Portal | Tax bills, assessed value, exemptions, and payment history are tied to the property’s BBL rather than its street address. | Confirming taxes match the listing and checking for tax arrears that could result in a lien. |
| ZoLa | The zoning district, allowed use, floor area ratio, and height limits for the lot, plus whether it sits in a special district. | Anyone planning to add space, convert use, or buy a development site. |
| PLUTO / MapPLUTO | The full tax-lot dataset behind ZoLa: lot size, building class, unit count, and more than seventy fields per lot, downloadable in bulk. | Investors comparing multiple lots at once, or anyone who wants the raw data rather than the map. |
| Discover NYC Landmarks (LPC) | Whether the building or block is an individual landmark or sits inside one of the city’s 141 historic districts, which caps what exterior work you can do without LPC sign-off. | Brownstones, prewar buildings, anything in a neighborhood that sounds historic. |
| DEP / My DEP Account | Water and sewer billing history and unpaid balances follow the property, not the previous owner. | Every purchase, since unpaid water charges over $1,000 can end up in the city’s annual tax lien sale. |
| NYC Flood Hazard Mapper | Current and projected coastal flood risk for the lot, beyond what the FEMA map alone shows. | Anything near the waterfront or in Zone A/AE per the FEMA Flood Map Service Center. |
| OER: Do I Have an E? / SPEED | Whether the lot carries an E designation for soil, air, or noise contamination, or appears in the city’s environmental remediation database. | Former industrial blocks, gas station sites, and any area rezoned in the last 20 years. |
| HPD Online | Multiple Dwelling Registration status, HPD housing code violations, and whether the current owner is even legally registered to rent the units. | Multifamily buildings with tenants, or any building with 3+ units. |
| OATH ECB Ticket Finder | Environmental Control Board fines tied to DOB, FDNY, DEP, or DSNY violations, including whether they’re still unpaid. | Always check alongside DOB NOW. A violation can show “resolved” on DOB while its fine is still open at OATH. |
What’s the one mistake that trips up almost everyone?
Treating “no open violation” as “fully clean.” It isn’t. DOB, HPD, and OATH run separate systems, and a violation can look closed in one while its penalty sits unpaid in another. An unpaid OATH judgment becomes a lien against the property, just like unpaid water bills, and neither shows up in a plain ACRIS search.
The other common one: skipping BIS because DOB NOW looks like the modern, complete system. It’s not, at least not yet. Older certificates of occupancy and pre-2010 filings often only live in BIS, and a building’s legal use traces back to whichever CO is on file, however old.
How does this actually catch problems? A real example.
Certificates of occupancy are the clearest case. A building’s CO is the legal record of what it’s allowed to be used for, and it doesn’t update itself when someone finishes a basement or adds a unit without a permit. Brick Underground has covered this repeatedly: a listing can show four bedrooms while the CO on file only permits three, because the fourth was never legalized.
Temporary certificates of occupancy add another wrinkle. A Brooklyn Law School review of TCO practice found that buyers routinely close on units covered only by a temporary CO, which expires and must be renewed, sometimes indefinitely, while the building never gets a permanent one. That status only shows up if you check DOB NOW or BIS directly, not from the deed.
This list is the reference version. For the narrative walkthrough of which sites matter most and why, see our due diligence guide. For the ownership and money side of a property, deeds, mortgages, and liens, that’s ACRIS territory. See our full ACRIS guide for how to search it.
FAQ
Do I need a lawyer to check these, or can I do it myself?
You can pull every record above yourself for free. A real estate attorney is still worth it for interpreting what an open violation or an E-designation actually means for your purchase and for handling the title search alongside it.
How is this different from checking ACRIS?
ACRIS is about ownership and money: deeds, mortgages, liens, and judgments. The sources here are about the physical property and what you’re legally allowed to do with it: permits, violations, zoning, flood risk, and contamination history.
Which of these matters most for a condo or co-op unit versus a house?
For co-ops and condos, DOB NOW, HPD Online, and OATH matter most, since building-wide violations affect every unit’s value and financing. For a house or small multifamily, add DEP water history and, near the water, the Flood Hazard Mapper.
Can an open DOB violation kill my mortgage approval?
It can. Lenders and their attorneys routinely pull DOB and HPD records before closing, and a serious open violation, especially one tied to an illegal conversion, can delay or derail financing until it’s resolved.
Is there one site that pulls all of this together?
Not officially. NYC Open Data hosts the underlying datasets for several of these agencies if you want to query them together, but there’s no single city portal that merges DOB, DOF, DEP, and LPC records into one lookup.
Nicole Fishman Benoliel co-founded NestApple in 2017. She's a lawyer admitted to the New York bar - her law degree is from La Escuela Libre de Derecho in Costa Rica, with further study at IE Business School in Madrid and an LLM from Fordham in New York. She does not act in a legal capacity at NestApple; every client is referred to an attorney who handles real estate deals full time.
