Many homes are equipped with an outside sewer clean-out that gives you access to your sanitary sewer house service. It is usually a plastic, clay or iron pipe located at ground level a couple of feet from the foundation of your house or by the street curb. It may be buried a few inches below ground level. Check your yard to see if you have one. In the event that the main sewer line is backing up into your house sewer line, removing the cap from your clean-out may keep it from backing up inside your home.