I have a two bathroom home with sewage pipes that go uphill. The sell isn't sewage just a burning tire scent that's not too heavy. When the home had only one toilet, there was no smell, and the odor is in the original bath not the new one. The new bath toilet leaks from under seat on the floor. Help!

You got to have the pipe camera to check the pipes. Hopefully you had a permit and the plumber was insured. Going to be costly