What unpermitted work is, and why the record barely holds it
Unpermitted work is construction, alteration, repair or demolition that required a City of Chicago permit and was carried out without one. The Municipal Code makes it unlawful to build, alter, repair, demolish or change the occupancy of a building without a permit unless the work falls within the exemptions, and that prohibition sits at § 14A-4-401.1 of the Chicago Construction Codes, with the exemptions at § 14A-4-402.
What a reader needs to understand first is that the City's record of unpermitted work is, in the ordinary case, nothing. There is no dataset of unpermitted work, no flag on an address, no field in the permit data reserved for work the City was not told about. A building record is generated when somebody applies for something, pays for something, or is cited for something. Work done quietly generates none of those events, so it generates no row. The absence in the file is the whole of the City's record of it.
That is the asymmetry this page exists to make legible. Unpermitted work is one of the most consequential things a buyer can inherit and one of the least visible things in the public record — and the shapes it does take, when it takes any at all, are oblique.
How it shows up, in the minority of cases where it shows up at all
There are three ways unpermitted work becomes visible in the City's published record, and each of them depends on something else happening first.
- Somebody complained, and an inspector was sent. The violations data distinguishes how an inspection arose, and the City's own field description names a complaint category for inspections resulting from a 311 complaint and a periodic category for inspections arising from a recurring cycle. The published description of that field is truncated, so the full list of categories cannot be stated here. A complaint-driven violation is the most common way unpermitted work enters the file, and it enters as a citation, not as a description of the work.
- A violation code names the omission directly. The Department's porch and deck inspection instrument, in use since 2004, carries code 002021 for the requirement to obtain a permit before performing work. Codes from instruments like that appear in the violation code field of the published violations data, which is how a failure to permit becomes a searchable fact about an address.
- A permit was obtained afterwards. The Department's homeowner guide describes resolving building code violations by obtaining a permit and having the work pass permit inspections. A permit whose issue date falls after the work was plainly done is a legalization record, and its date relative to the physical evidence is the entire story it tells.
None of these is a record of the unpermitted work itself. Each is a record of the City reacting to it.
What the absence of a permit proves
On its own, nothing. Four separate and entirely different situations produce an identical empty permit history, and the file does not distinguish among them.
The work was exempt. A great deal of lawful Chicago work requires no permit. The Department's homeowner guide lists interior finishes such as paint, carpet, tile and wallpaper; in-kind replacement of certain fixtures and equipment in buildings of up to three units and three stories; roof shingle work on steep slopes; up to 1,000 square feet of drywall where nothing structural, plumbing, electrical or ventilation-related changes; up to 250 bricks; low-voltage wiring; fences up to five feet; sheds up to 70 square feet; gazebos up to 150 square feet. The Department's current porch page adds residential porches under six feet off the ground with no more than 50 square feet of landing area, and routine maintenance such as replacing deck boards, stair treads and railing pickets where no code violation is involved. The guide states its code information was correct as of July 2017, so treat that list as the structure of the exemptions rather than the current legal test.
The work was unpermitted. Same empty file.
The work predates the published data. The permit dataset states coverage from 2006 to the present. For a building put up in the 1920s, the published history covers a recent fraction of its life.
The permit existed and was removed. The dataset description states that it excludes permits voided or revoked after issuance. A revoked permit does not appear marked as revoked; it is simply not there.
Source: Guide to Building Permits, City of Chicago Department of Buildings, October 2019.
No permit found and no work done are different statements
This is the sentence the page is built around, and the slide between the two is the single most common error made with Chicago permit data.
No permit found is a statement about a search of a published dataset. It means that a query against a particular record system, covering a particular period, excluding a particular class of removed records, returned nothing for a particular address string. Each of those qualifiers is doing work. Change the period and the answer changes. Search the lot rather than the street number and the answer can change, because the City's violations data carries a property group field precisely because lots in Chicago commonly have multiple point addresses, range addresses and buildings.
No work done is a statement about a physical building. Nothing in the first statement supports the second. A kitchen can be gutted and rebuilt, a basement finished, a porch reframed and a service upgraded without a single row appearing — some of that lawfully exempt, some of it not, and the file identical either way.
The error runs in the other direction too, and it is just as common. A thin permit history is often read as evidence that a building is original and untouched, which is a conclusion the record cannot support. And the absence of a porch permit is not evidence that a porch is original, because so much porch work is exempt by the Department's own current description.
What the record proves when something is actually there
Where a trace does exist, it is worth knowing exactly how far it reaches.
A violation citing the requirement to obtain a permit before performing work proves that an inspector attended on a date and wrote that down. It does not prove that anyone was found liable: the City states that its violations data contains cases where a respondent was found liable and cases where a respondent was found not liable, undifferentiated. And a status of Complied means the file was closed, which the City pairs with a warning that the data does not necessarily reflect the current condition of the building.
A later permit for work that visibly predates it proves that the City authorized work at that address under that description. It does not prove the earlier work was brought to standard, because the permit record carries no inspection outcome at all — the published permit data has no field for whether a final inspection occurred or passed.
And a permit for something else proves nothing about the thing in front of you. The permit data's work description field is the City's record of what was authorized. There is no field anywhere recording what was built. The only mechanism that ever connects authorization to execution is an inspection, and the City of Chicago Office of Inspector General's 2022 audit found required inspections completed on 98.9% of permits requiring a certificate of occupancy against 16.7% of those that do not. A follow-up in June 2024 found the Department had not implemented the corrective action the audit recommended.
Where the records question ends
A reader who has read a permit history carefully has established a bounded set of facts: that certain work was authorized on certain dates under certain descriptions, that certain inspections produced violations, and that the file is silent about everything else. That silence covers exempt work, unpermitted work, pre-2006 work and removed permits without distinguishing among them.
The physical question — whether the work in front of you was done competently — is not answerable from any of this. It is answerable by looking at the building, which is a different discipline entirely and produces a different document. The records establish the paper position; a physical examination establishes the condition; neither substitutes for the other, and a buyer who has only one of the two has half the picture.
The consequences question is different again. What unpermitted work means for a particular purchase depends on the contract, on the title commitment, and on advice from counsel. This site is a reference on what the City's records prove. It is not legal advice, and nothing here describes how anyone should deal with the City about a building.