A certificate of occupancy (CO) is the building department’s record that a building, or a change to it, passed its final inspections and can be used for the stated purpose. To look one up, search the permit records of the department that issued the building permit, by address or parcel number. In Miami-Dade County, new single-family homes typically received their CO about eight months after the permit was issued, but more than a third of new-home permits from 2020 to 2022 still show no CO date.
What a certificate of occupancy tells a buyer
A CO ties a building to a legal use, such as a single-family house or a 12-unit apartment building, and confirms the work under the permit was finished and approved. Some departments issue a certificate of completion (CC) instead for work that doesn’t create new living space, such as a pool or a detached structure. Whether a house has a CO at all depends on where it is and when it was built.
- New construction: most departments issue a CO when a new house or building passes its final inspections.
- Older houses: many cities did not require COs until the mid-1900s. Seattle, for example, first required them in 1956, so older Seattle houses that haven’t changed use may have no CO on file.
- Alterations: remodels usually end with a final inspection, not a new CO, unless the work changes the use or number of units.
If a CO is missing, the next record to look for is the final inspection on the building permit. Our permit status decoder explains what labels like Finaled, Expired, and CO Pending mean.
How long a CO took on 5,229 Miami-Dade new-home permits
We downloaded Miami-Dade County’s building permit data (Miami-Dade County open data, Building Permits Issued By Miami-Dade County – 2 Previous Years to Present, pulled October 23, 2026) and measured the days from permit issue to the CO or CC date the county records on each permit. We used master building permits issued from 2020 through 2022, so every permit has had nearly four years or more to reach a certificate. Use categories below are the county’s; additions and alterations are limited to single-family and townhouse properties. The numbers are our own calculation from county records, not figures published by Miami-Dade County.
| Work (county permit type) | Master permits issued 2020–2022 | Have a CO or CC date | Days from permit issue to CO/CC (median) | Slowest 10% took at least |
|---|---|---|---|---|
| New single-family house or townhouse | 5,229 | 63% | 238 | 542 days |
| New duplex | 344 | 56% | 290 | 908 days |
| New apartment building, 5+ units | 140 | 86% | 655 | 1,005 days |
| Addition, attached (single-family) | 1,176 | 70% | 474 | 1,281 days |
| Interior alteration (single-family) | 1,365 | 82% | 317 | 1,017 days |
| Exterior alteration (single-family) | 9,611 | 20% | 149 | 701 days |
| Addition, detached (single-family) | 3,562 | 22% | 104 | 690 days |
Three things stand out for anyone buying a house in unincorporated Miami-Dade.
- Most new houses got their CO within a year. The median new single-family permit reached its CO 238 days after issue, and 51% of all new-house permits had a CO within 365 days. The slowest 10% of those that finished took 542 days or more.
- 37% of new-house permits from 2020–2022 show no CO date. That is 1,946 of 5,229 permits, nearly four years or more after issue. If you are buying a house built in the last few years, ask the seller for the CO and check it against the permit number in the county’s records before closing.
- Attached additions take longer than new houses. An attached addition took a median of 474 days to reach its certificate, about twice as long as a new house, and 29% of those that finished took more than two years. A recent addition without a CO or CC is the item to ask about. A missing date on exterior work, such as windows or shutters, is common in this data (80% have none) and means less.
Limits of this count: the county’s data covers permits issued by Miami-Dade County, not cities that run their own building departments. The data set has one date field for both CO and CC and does not say which one was issued. A permit without a date may have been closed another way, replaced by a later permit, or still be open. One record with an unreadable date was left out.
How long a CO took in New York City and Los Angeles
We ran the same check on New York City jobs that received their first permit, and Los Angeles permits issued, from 2020 through 2022. Each city records the certificate differently, so the start and end points differ slightly; the definitions follow the list. The numbers are our own calculation from city open data, pulled October 24, 2026, not figures published by the cities.
- New York City, new one- or two-family building (797 jobs, 2020–2022): 89% have a final CO. Median 483 days from permit to CO; the slowest 10% took at least 1,002 days.
- New York City, new building of other types (417 jobs, 2020–2022): 74% have a final CO. Median 702 days from permit to CO; the slowest 10% took at least 1,244 days.
- New York City, Alteration CO (change of use or occupancy) (2,147 jobs, 2020–2022): 58% have a final CO. Median 530 days from permit to CO; the slowest 10% took at least 1,173 days.
- Los Angeles, new one- or two-family home, not an ADU (6,533 permits, 2020–2022): 85% have a final CO. Median 462 days from permit to CO; the slowest 10% took at least 1,120 days.
- Los Angeles, new accessory dwelling unit (ADU) (3,256 permits, 2020–2022): 83% have a final CO. Median 504 days from permit to CO; the slowest 10% took at least 1,106 days.
- Los Angeles, new apartment building (615 permits, 2020–2022): 75% have a final CO. Median 1,016 days from permit to CO; the slowest 10% took at least 1,544 days.
- Miami-Dade, new single-family house or townhouse (table above) (5,229 permits, 2020–2022): 63% have a final CO. Median 238 days from permit to CO; the slowest 10% took at least 542 days.
- New York City: days from a DOB NOW job’s first permit to its first certificate filed as “Final” in DOB’s DOB NOW: Certificate of Occupancy data, matched by job number to DOB NOW job filings. Withdrawn filings are left out.
- Los Angeles: days from permit issue to the certificate of occupancy date LADBS records on each original permit (LA Open Data, Building Permits Issued). ADUs are permits whose description mentions an ADU or accessory dwelling unit.
- Miami-Dade: days from permit issue to the CO or CC date on the master permit, as described above.
Three things stand out.
- A new house typically waited well over a year for its CO in both cities. The median was 483 days in New York City and 462 days in Los Angeles, about twice Miami-Dade’s 238 days. Most of that is construction time, not paperwork, since the clock starts when the permit is issued.
- Some buildings run on temporary COs. In New York City, 10% of these jobs (380 of 3,710) have only Initial or Renewal certificate records and no Final one yet, including 15% of larger new buildings. DOB says a temporary CO typically expires 90 days after issue and must be renewed until the final CO is granted (NYC DOB, Temporary Certificate of Occupancy). Ask which kind the building has.
- Change-of-use jobs are the ones most often left without a certificate. 29% of New York City Alteration CO jobs have no certificate record at all, against 9% of new one- and two-family buildings. If a New York City listing describes a conversion, look for the Alteration CO job and its Final certificate.
Put together with our data on how long building permits take: a typical new one- or two-family home in Los Angeles waited about 270 days for its permit and then about 462 more days for its certificate; in New York City, a typical new building waited about 275 days for a first permit and then about 574 more for a Final CO. These are medians of separate groups, so treat the total as a rough guide, not a forecast for one project.
Limits of this count: permits from 2022 have had less time to finish, so their share with a CO will still rise. In New York City, a building can hold one active CO at a time, so a later job on the same building can replace an earlier job’s certificate. An earlier version of this page cited 74% for New York City new buildings from 2020–2023 using DOB’s sign-off date; the figures above use the certificate records themselves and a 2020–2022 window.
How to look up a certificate of occupancy in five places
Start with the department that issued the building permit. These are the official routes we confirmed.
- New York City: COs issued from July 2012 to March 2021 can be viewed as PDFs in the DOB Building Information System (BIS): choose Building Information Search, enter the borough and address, and open the property profile. COs issued since March 2021 are in DOB NOW, and DOB publishes them as the DOB NOW: Certificate of Occupancy open data set.
- Los Angeles: use LADBS Search Online Building Records, which covers building permits and Certificates of Occupancy and searches by address. If a CO isn’t available as a PDF, email the Records Research Request Form to the LADBS Records Section.
- Miami-Dade County: the county’s building plans and permits public records page links to the online Certificate of Occupancy/Completion search and a separate Certificate of Use search. Our Miami-Dade permit search guide covers addresses inside cities with their own building departments.
- Seattle: SDCI records from 2005 to the present are in its online Permit and Property Records library and the Seattle Services Portal; 1894–2004 records are in the SDCI Microfilm Library. SDCI’s Tip 120 explains COs, including that older buildings that haven’t changed use may have none. Our Seattle permit guide walks through the search.
- Chicago: the Department of Buildings requires a CO mainly for residential buildings with four or more units and larger nonresidential buildings; owners of single-family homes may request one, but only before work begins (Chicago DOB, Certificates of Occupancy). Most Chicago houses therefore have permit and inspection records but no CO.
In Seattle, houses and duplexes get no C of O at all; our Seattle certificate of occupancy guide explains which buildings get one and how long 4,205 recent new-housing permits took to complete.
If the house has no certificate of occupancy
A missing CO is not always a problem. Check three things in order: whether the place and era required one, whether the permit shows a final inspection, and whether the property’s current use matches the last approved use. If a recent new house or addition has no CO, ask the seller for it in writing and confirm with the issuing department before closing.
If the work was done by a contractor, check that the license on the permit was active and covered the work with our contractor license lookup guide.
If added living space has no CO and no permit, our guide to unpermitted work on a house lists what to check next.
Department pages checked October 23, 2026.
For New York City addresses, our NYC certificate of occupancy lookup covers DOB NOW and BIS and shows how many jobs still run on temporary certificates.
Los Angeles: our Los Angeles certificate of occupancy guide covers PRISM and how long 16,018 new-home and ADU permits took to reach a certificate.
New Jersey: our NJ certificate of occupancy timeline shows how long new houses permitted in 2021–23 waited for a CO, town by town, and why the state file often shows none.
More from our permit data: what public permit records show across seven places.