A New York City building permit tells you three things: what kind of job it is (a code such as NB, A1, A2 or A3), what trade the permit covers (general construction, plumbing, a sidewalk shed), and when it expires. What it does not tell you is whether the work was done well, or done at all. And there is one structural trap worth knowing before you read any building's record: the permit history splits in two in June 2020, when the city moved permitting from the old Buildings Information System to DOB NOW.
The split: DOB NOW and BIS
The Department of Buildings ran permitting through the Buildings Information System (BIS) for decades. It has been migrating to DOB NOW, its current online system, and the two hold different eras of the record. The city publishes both as open data, and the boundary is sharp: the legacy BIS permit file's most recent issued permit is dated 5 June 2020. Nothing has been added since. The DOB NOW permit file picks up from there and now holds about 978,000 permits.
This is the single most common reason a building looks like nothing has happened to it in six years. It has; the work is in the other file. Filings made in DOB NOW do not appear in BIS at all, and DOB has said the DOB NOW public portal will replace BIS only once everything has been deployed there — existing BIS data stays available in the meantime. Any honest lookup has to read both, which is what Check a Building does.
Job types: NB, A1, A2, A3
The job type is the most informative single field, because it tells you the ambition of the work. In the legacy file the codes and their volumes look like this:
| Code | Means | Permits on record |
|---|---|---|
| A2 | Alteration, multiple work types, no change to use, egress or occupancy | 2,389,571 |
| NB | New building | 571,570 |
| A1 | Alteration that changes use, egress or occupancy — needs an amended certificate of occupancy | 434,689 |
| A3 | Minor alteration, one work type, no change to use, egress or occupancy | 413,615 |
| DM | Demolition and removal | 102,288 |
| SG | Sign | 78,007 |
The line that matters for a tenant is between A1 and everything else. An A1 is the city acknowledging that the building's legal use, its means of exit, or how many people may occupy it is changing — which is why it ends in an amended certificate of occupancy. If your building shows an A1 and the number of legal apartments changed, that is a fact worth understanding; see what a certificate of occupancy is. An A2 covering several trades is ordinary renovation. An A3 is usually something small and self-contained.
DOB NOW reorganises this. Filings there are described as New Building, Alteration-CO (work that changes use, egress or occupancy and so needs an amended certificate) or plain Alteration. The distinction survives the rename: what matters is still whether the certificate of occupancy has to change.
Work types: what trade the permit covers
A single job usually needs several permits, one per trade, each pulled by the licensed contractor doing that work. In the DOB NOW file the commonest are:
| Work type | Permits |
|---|---|
| General Construction | 204,216 |
| Plumbing | 151,279 |
| Sidewalk Shed | 107,229 |
| Mechanical Systems | 92,874 |
| Construction Fence | 83,461 |
| Structural | 59,464 |
| Sprinklers | 56,719 |
| Supported Scaffold | 53,620 |
This is why a building with one renovation can show a dozen permits at once, and why counting permits is a poor measure of how much is happening. Two of the entries above are not construction at all: a sidewalk shed and a supported scaffold are protective structures, and a shed permit that keeps being renewed year after year is usually a facade problem rather than a project — see Local Law 11 and FISP.
Expiry: why so few permits last a year
DOB states the rule plainly. A permit issued in DOB NOW expires at the earliest of three dates:
- the expiry of the contractor's insurance — general liability, disability, or workers' compensation;
- the expiry of the contractor's licence;
- one year from the date of issue.
People remember the third and forget the first two, which is why "a permit lasts a year" is the usual wrong answer. Take every permit the city issued in a single month — January 2026, 12,915 permits — and measure how long each one actually ran:
| Permit life | Share |
|---|---|
| The full year (365–366 days) | 20.4% |
| Less than a year | 79.6% |
| Less than six months | 24.1% |
| More than 366 days | 0% |
The median permit in that month ran 276 days. Four in five expired early, almost always because an insurance certificate or a licence ran out first. Nothing sinister is happening: DOB will extend a permit automatically at no cost if the insurance or licence is renewed before the expiry date, and otherwise the contractor renews and pays a $130 fee. It does mean an expired permit is weak evidence of an abandoned job. Renewals are common enough to be visible in the data: of all DOB NOW permits, about 665,000 are initial permits and about 306,000 are renewals.
Status codes
DOB NOW keeps permit status simple — the file holds roughly 623,000 permits marked Signed-off and 355,000 marked Permit Issued. The legacy BIS system used single-letter job status codes, which is what you will see on older records:
| Code | Means |
|---|---|
| A | Pre-filed |
| D | Application processed, completed |
| H | Plan exam in process |
| J | Plan exam disapproved |
| P | Plan exam approved |
| Q | Permit issued, partial job |
| R | Permit issued, entire job |
| X | Signed off |
| 3 | Suspended |
The useful reading is that a job which reached P was approved but not necessarily permitted, a job at R was permitted, and only X means the work was signed off as complete.
Reading a permit record, in order
- Check which file the permit came from, because that tells you the era: anything issued up to 5 June 2020 is a legacy BIS record, anything later is DOB NOW.
- Read the job type before anything else. A1 or Alteration-CO means the building's legal use, egress or occupancy was changing; NB means a new building; A2 and A3 mean the certificate of occupancy was not affected.
- Read the work type to see which trade the permit covers, and expect several permits for one job rather than one.
- Compare the issue date against the expiry date. Most permits run short of a year because an insurance certificate or a licence expired first, so an early expiry is ordinary rather than suspicious.
- Check the status. Only a signed-off permit says the work was completed and accepted; issued means it was authorised to start.
- Look at what is missing. Work with no permit at all leaves no permit record, so pair this with the building's violation history before concluding a building has been quiet.
What a permit does not tell you
- Not a quality judgement. A permit authorises work to begin. It records no inspection result.
- Not proof the work happened. Permits are pulled and jobs are abandoned. Sign-off is the field that speaks to completion.
- Not a complete picture of the building. Work done without a permit leaves no permit record — it leaves a violation record instead, which is a different file. See how to check a building's violations.
- Not a statement about the contractor. The permit names the licensed permittee. That is a fact about who was authorised to do the work, and nothing more.
- Not the same as a certificate of occupancy. A permit lets work start; an amended certificate records what the building legally became afterwards.
Reading your own building
Search any address at Check a Building and the permit section reads both files at once, legacy and DOB NOW, so the June 2020 boundary is not something you have to remember. New permits across the city also appear in the Just permitted feed on the home page as they are issued. Related reading: DOB NOW vs BIS and BIN, since permits are filed against the building identification number rather than the tax lot. If a permit at your building has stopped, what a stop work order means covers the other reason work halts.
General information about public building records, not legal or construction advice, and not tenant screening. Counts are live totals from NYC Open Data on the date queried and will move. Sources: NYC DOB — Job Types and Codes, Permit Renewal, and Guide to BIS, DOB NOW and eFiling; NYC Open Data — DOB Permit Issuance (ipu4-2q9a) and DOB NOW: Build Approved Permits (rbx6-tga4).