I received a phone call from a friend about a smell in the basement. They were sure it was sewer gas. There had been some maintenance done in the street; could have it resulted from that?
The first question is to make sure you know the difference between the smell of sewer gas and natural gas. Natural gas has a very distinctive “rotten egg” smell. If you have never smelled either you may need someone with an experienced nose to point out the difference. Otherwise what you smell may be a pair of stinky sneakers.
You really should know what natural gas smells like so that if you ever smell it you know to get out of the house and call the fire department. It isn’t something you want to mess with.
It you do smell sewer gas, the most likely culprit is a drain trap that has dried out. Places to check are floor drains, tub and shower drains, sink drains and toilets. If these are not used regularly they can dry out and let the sewer gas into the house. Make sure to run water in them every few months. You can pour a bucket of water into the floor drains. Another possibility is if the wax seal at the base of a toilet has been compromised and is allowing the gas to escape.
There are other possibilities that allow sewer gas to escape such as a broken vent pipe but that’s less common. In those cases it may require a plumber with specialized equipment to locate the source.
After I talked to my friend I found out that there was a bathroom in the basement that was rarely used. They ran water in all the drains and the smell went away. They were relieved that their fears of a much larger job didn’t come to pass.
Philip
