Trap on main sewer line?
After hurricane sandy destroyed my basement with backed up sewer water, we decided to put a backwater valve on our main sewer line. Our main sewer lines comes into the house about 2' below our basement floor, and is accessible in a "pit" near the front of my house. Coming into my house I have a 4" cast iron pipe, which then attaches to a double trap ( it has two clean outs) then there is a tee which goes to a vent. the vent and everything after that is PVC. I have been told that plumbing codes no longer require traps on the main sewer line by some plumbers, others tell me I need one. I am located in Staten Island, NY. I would be very happy if I was not required to have one, because I could take out the trap and Put in the backwater valve. If I need the trap then that means a LOT of breaking of cement. Any advice on how to proceed? Should I take out the trap? The house is about 15 years old. There are no drains without traps anywhere in the house.