Do you need a building permit for a deck addition?

I am installing a hot tub on the side of my deck that will sit at the base of a retaining that the deck is on. So I have to build some stairs off the back of my deck that will extend down ten or so feet to the ground, and I plan to build at the base of the stairs a 6x10ft wooden patio that will run along the side... show more I am installing a hot tub on the side of my deck that will sit at the base of a retaining that the deck is on. So I have to build some stairs off the back of my deck that will extend down ten or so feet to the ground, and I plan to build at the base of the stairs a 6x10ft wooden patio that will run along the side of the hot tub. Does this work require a city building permit? Also, how deep in the ground should the support beems for the stairs go? Should I worry about water lines or phone lines if their is an electrical poll that is 15ft from the site on the other side of my fence? A lot of question, but I don't want to get in a bind doing this. Thank you so much for your help!
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