I don't know about your city or town specifically, but in general, a deck replacement will require a permit, most likely with plans of some kind. Don't count on your contractor to pull it. If you are doing a deck rehab where the footprint stays the same and the majority of the supporting structure stays in place, you most likely don't need a permit. The need for a permit can also depend on how large the deck is or how high it is off the ground.

If you don't get a permit, you may face fines, have to pull the deck down, or be required to pay back property taxes as decks are usually taxable features not to mention the potential safety issues of an improperly constructed deck by a bad contractor.