I have been having sewer gas smell in my house for the past few years every summer. Recently I have been having some health conditions that I believe are related to these gases. I called out a plumber and the prices they quoted are not feasible for me. So I did a bit of DIY, and found where the leak was coming from, in a pipe that goes almost under the house. This pipe will be very hard to repair without digging in from outside of the house. So my question is will putting a p-trap on the main line into the house stop the sewer gas from completely coming in???? Or is there something im not understanding here.