We have just purchased a house that we are remodeling and adding a new bathroom. It has an existing half bath(unpermitted) and full bath. Today the plumber tried to flush the toilet in the half bath and the water instead of going down all the way, went down a little and then came back up. He said that this is an indication of something being wrong with the Main Line and we should get a camera to check? My father put water hose through the opening where the toilet from the other bathroom was and the water went through. Do you think that is an indication that the Main Line is fine?