Northern Missouri
Buchanan County permits include buildings and septic systems
Buchanan County Planning and Zoning lists building, land-disturbance, and septic permits, and says all zoning districts require a building permit for structures.
A rural project can need a permit even when it feels small.
In unincorporated Buchanan County, Planning and Zoning is the front door for building and land-use questions. County permit materials cover building permits, demolition or removal permits, land disturbance permits, septic system permits, sign permits, and buildings over 100 square feet. The county also treats onsite wastewater as part of the permit path when it applies.
That does not mean every project has the same review. It means a shed, addition, sign, land disturbance, or septic change should start with the right jurisdiction.
First sort out whether the address is inside St. Joseph, another city, or county jurisdiction. Then use the permit office that controls that address.
References
Where this fits: this note belongs to Buchanan County. See every local note for the county on its page.