The permit fee is the one number in a retroactive permit you can look up in advance. Cities publish it, the penalty is written into the same schedule, and the arithmetic is simple.
It is also rarely the number that decides the project. This article covers what cities actually charge to permit work that was already built, then what sits around that charge, which is where the money usually goes.
For the process itself, the documents, the inspections and the situations where legalization is not possible, see our full guide to retroactive permits.
The Penalty Is Almost Always Exactly Double
Published penalties for unpermitted work are more consistent than most permit rules. Five of the six schedules read for this article set the penalty at 100 percent of the permit fee. You pay the fee, then you pay it again.
| Jurisdiction | What the schedule says |
|---|---|
| Miami-Dade County | "an additional fee of one hundred percent 100% of the usual permit fee in addition to the required permit fee" |
| Orlando | "Violation Penalty, work without a permit: An additional 100% of applicable permit fee" |
| Cincinnati | "INVESTIGATION FEE (for projects commenced without a permit)... equal to the applicable permit fee and is charged in addition to the permit" |
| Chandler, Arizona | "Permit fees are doubled for building without a permit" |
| Fort Worth | "An investigation fee, in addition to the permit fee, shall be collected whether or not a permit is then or subsequently issued. The investigation fee shall be equal to the amount of the permit fee" |
"Investigation fee" and "double fee" are the same thing. Cincinnati and Fort Worth use the first name, Miami-Dade the second, and the arithmetic is identical. If your city's schedule has no line called "penalty," look for an investigation fee before concluding there is no charge.
Two details from those schedules are worth knowing before you call the department:
- Fort Worth charges it "whether or not a permit is then or subsequently issued." Applying and then abandoning the application does not avoid the fee.
- Miami-Dade adds that payment "shall not relieve the applicant of other penalties established by law." The doubled fee is a permit charge, not a settlement of the code violation.
Fort Worth does allow an appeal: an applicant may ask the city council to reduce the investigation fee, but "in no case may the fee be reduced to less than the actual investigation costs incurred by the city."
Chicago Is the Exception, and It Runs the Other Way
Chicago does not use a multiplier. Its Construction Codes set the penalty in a graduated table, Table 14A-12-1204.4, keyed to the size of the regular permit fee:
| Regular permit fee | Penalty |
|---|---|
| Up to $500 | 100% of the regular permit fee |
| $501 to $1,000 | $625 |
| $1,001 to $1,500 | $750 |
| $1,501 to $2,000 | $875 |
| $2,001 to $2,500 | $1,000 |
| $2,501 to $3,000 | $1,125 |
| $3,001 to $3,500 | $1,375 |
| Over $3,500 | $1,375 plus $75 for each $500 increment above $3,500 |
Read the middle of that table carefully, because it is the opposite of what people assume. A $600 permit fee draws a $625 penalty, slightly more than double. A $3,000 permit fee draws $1,125, which is 37 percent, not 100. Chicago's penalty gets proportionally smaller as the job gets bigger.
There is a separate and much harsher line in the same section. Where the stop work order was issued because the work was done by someone lacking a required trade license, or by someone who should have been listed on the permit application and was not, the penalty is calculated on the regular permit fee plus $1,000. Using an unlicensed trade is the expensive mistake, not the missing permit.
What Doubling Actually Costs You
Doubling sounds alarming until you put a real permit fee into it. For the accessory projects most homeowners are legalizing, the permit fee is modest, so the penalty is modest too.
Using fees published by the cities themselves: a fence permit that runs $45 in Savannah, $80 in Sandy Springs, $98 in Phoenix or $150 in Chicago produces a penalty of about the same again. Doubling a $98 fence permit costs you $98. That is not the number that makes retroactive permits expensive.
The penalty is the small, predictable part. The costs that actually vary are the ones the process demands after the fee is paid:
- As-built drawings. A few hundred dollars from a licensed drafter for a simple exterior structure. $1,500 to $5,000 for a finished basement or an addition.
- Trade contractor letters, where concealed electrical, plumbing or mechanical work has to be certified, typically $150 to $500 per trade.
- Corrections. Zero if the original work meets current code. The largest single line in the project if it does not.
- Cosmetic restoration after destructive testing, where inspectors have to open finished surfaces to see hidden work.
For an exterior project, a deck, shed, patio, fence or detached garage, most of that list does not apply. An inspector can see the whole structure from outside, so there are no trade letters and no walls to open. What is left is the doubled permit fee and a straightforward as-built drawing. That is why legalizing a shed is a few hundred dollars and legalizing a basement is not.
The Cost That Decides Everything Is Not a Fee
There is one question that determines whether any of the above is worth spending, and it is answered by the cheapest document in the stack.
Every expensive item on that list describes how the work was built. None of them addresses where it sits. A structure inside a required setback, over an easement, or across a property line does not become legal because the framing is sound and an electrician has certified the wiring. It moves, or it comes down, and the money spent on drawings is gone either way.
The site plan is the drawing that answers that question, and it is the one to commission first. It shows your lot lines, the setback lines for your zoning district, any easements, and where the structure actually stands relative to all three. If it shows a problem, you have found it for a small fraction of what the rest of the application would have cost, and you can take a variance, a partial legalization or removal to the department before spending anything else.
If you need one drawn from your parcel data, we produce permit-ready site plans.
How to Get Your Own Number in Ten Minutes
The schedules are public and the arithmetic is simple.
- Find your city's permit fee for the work as if it were new. Most cities publish a fee schedule as a PDF. Search for the project type by name rather than assuming a category.
- Search the same schedule for "investigation," "double" or "penalty." That line is the multiplier. If it is absent, call and ask specifically, because it usually exists somewhere in the code even when it is not in the fee table.
- Add plan review if your city charges it separately, which many do as a percentage of the permit fee.
- Ask one question on the phone: whether the department reviews retroactive work against the current code or the code in effect when the work was built. The answer changes what corrections will cost far more than any fee does.
If the work has already been flagged by an inspector or a neighbor complaint, our guide to what happens if you build without a permit covers the enforcement side, and permit applications that get rejected covers what to do when the review comes back with corrections.
The Bottom Line
Expect to pay the permit fee twice. That is what five of six published schedules say, and Chicago's graduated table only departs from it on large jobs, where the penalty is proportionally smaller rather than larger.
For an exterior structure, doubling a modest permit fee is not the obstacle people fear. The real variables are the drawings, the corrections, and above all whether the structure is in a place the zoning code allows. Answer the location question first, with a site plan, and the rest of the budget becomes predictable.