You should hire a sewer service professional to unclog a main sewer line with tree roots. Tree roots can grow into the main sewer line, and this problem requires a specialized hydro jet, or rooter, that is powerful enough to clear the roots. The tree can also damage the main sewer line, and a professional will need to make repairs or replace the damaged sections. Sewer line replacement costs about $60 to $250 per linear foot.

It is generally safe to stay in a house that smells like sewage for a short time, but you should get the problem fixed as soon as possible. While the level of sewer gas is usually low enough to only cause minor symptoms, prolonged inhalation can lead to headaches, nausea, or respiratory irritation. High levels of gas exposure can be more dangerous, and high concentrations of methane—a component of sewer gas—can pose an explosion risk in enclosed spaces. If you smell sewer gas in your home, ventilate the area and call a professional to locate, assess, and fix the problem, as it will not go away on its own.

Homeowners insurance usually doesn’t cover sewer backups because it’s typically an avoidable problem with proper maintenance. The only exception would be if the backup is occurring because of local flooding and only if your city uses a combined drainage system for stormwater and sewage. If that’s the case, your policy should cover any resulting damage.

To get rid of a sewer smell in your crawl space, you’ll have to find the source of the problem. If it has to do with your sewer lines, then repairing the line will help. You may need to make other repairs, like fixing your sump pump or encapsulating your crawl space to reduce moisture. After you make the repair, depending on the issue, you may still need to clean out your crawl space to get rid of the stink.