Have a Tax Question? Ask a Tax Expert
Just getting permits does not mean that the county knew about your property or was prepared to inspect it for tax purposes. You must list your property with the county and notify them if you make improvements that will increase the value within a reasonable amount of time after the building is complete.
It looks like you forgot a step or were unaware of what you needed to report.
Unfortunately, you will owe this tax.
Let me know if you have more questions.