PLUMBING SMOKE TEST FOR RATS
Simple, ingenious and just as effective, the smoke test process involves blowing smoke into sewer and drainage pipes in order to locate the cause of bad odors and the routes by which they enter the house, identify problems caused by rodents (rats), isolate possible water leaks and unmask dangerous gas leaks. When it comes to gas leaks, sewage gases usually have a penetrating "rotten egg" odor and can include methane, a gas that can cause an explosion, or hydrogen sulfide, a lethal gas. The smoke test methodology leaves no residue or stain and is safe.