Missouri permit requirements
We have read and dated 20 permit rules across 2 jurisdictions in Missouri. They do not all say the same thing: shed thresholds alone run from 50 to 200 sq ft across 2 of them.
- Jurisdictions
- 2
- Verified rules
- 20
- Permit always required
- 2
- Depends on the project
- 17
Do Missouri jurisdictions agree?
Every row below is a measurement at least two Missouri jurisdictions publish, compared against each other. This is the question a statewide answer cannot settle, because the number that governs your project is the one your own city or county publishes.
| Project | Published threshold | Jurisdictions | Agreement |
|---|---|---|---|
| Shed | 50 to 200 sq ft | 2 | 2 different numbers |
| Deck | 12 to 30 inches | 2 | 2 different numbers |
0 of 2 comparable measurements are uniform across Missouri; 2 are not. Latest verification 2026-08-16.
Where Missouri jurisdictions split
The verdict for each project across the 2 Missouri jurisdictions we cover. On 1 of 10 projects they do not give the same answer, which is why a statewide answer is not one.
| Project | Permit required | Depends | No permit | Across the state |
|---|---|---|---|---|
| Fence | 1 | 1 | Answer varies | |
| Deck | 2 | Same answer everywhere | ||
| Electrical | 2 | Same answer everywhere | ||
| HVAC | 2 | Same answer everywhere | ||
| Patio | 2 | Same answer everywhere | ||
| Plumbing | 2 | Same answer everywhere | ||
| Pool | 2 | Same answer everywhere | ||
| Roof Replacement | 2 | Same answer everywhere | ||
| Shed | 2 | Same answer everywhere | ||
| Solar | 2 | Same answer everywhere |
Building without a permit in Missouri
Missouri has no statewide residential building code and no state crime of building without a permit, so both the permit requirement and its penalty come from city or county ordinance. Where a municipality enforces under its zoning enabling act, RSMo 89.120.2 makes it a misdemeanor to erect, construct, reconstruct, alter or convert a building in violation, punishable by not less than $10 and not more than $250 for each and every day the violation continues, or imprisonment for 10 days for each day it continues, or both, rising to $100 to $500 per day for a second or subsequent offense at the same building; in a city with more than 300,000 inhabitants the range is $10 to $500 per day and $250 to $1,000 per day for repeat offenses.
Penalties, the as-built path, and what the statute actually says
What you can build without a permit in Missouri
1 of the 20 answered rules across Missouri need no permit at all and 17 turn on a size or scope condition the jurisdiction publishes, by project and jurisdiction, in each office's own words.
What each Missouri jurisdiction publishes
One line per jurisdiction, written from its own rules rather than from a state summary. This is the section that used to be a list of links, and the states with the fewest jurisdictions to compare are the ones it says the most about.
- Kansas City 10 rules
9 of 10 projects need a permit, and 1 does not. Only solar work always needs one. No permit at all for fence. Published thresholds include deck at 30 inches and pool at 5,000 gallons.
- St. Louis 10 rules
1 of 10 projects always need a permit and 9 turn on the size or scope of the work. Only solar work always needs one. Published thresholds include deck at 12 inches and shed at 50 sq ft.