For a deck related to an IRC or IBC structure:
KMC 21.06.215: A building permit is not required for a deck that is not more than 30" above grade and not over any basement or story below and which is not part of an accessible route.
NOTE: Even when a building permit is not required, it is the responsibility of the person building the deck to ensure it meets related code requirements. Skip to Step 4.
A building permit is required when the deck is more than 30" above grade, located over a basement or story below, or part of an accessible route.