Sewers

If basement floor drains have seen no water in ten years, traps must be dry, so what stops sewer gas entering?

I don't even know if these drains are connected to the vent stack like other drains, but I have to assume they're on the same sewer line, so...?

Public Comments

1. pour some water in them to be sure, you could also cover them with a plastic lid from a coffee can or a similar container or piece of rubber
2. If these drains are simply floor drains and are lower than the main sewer line that leaves your house, they are not hooked up to a sewer or septic system. These are flooding drains, designed to drain out water, and while usually piped away from the house (some are just open to a gravel pit in the ground), are, understandably, not part of a sewer because a major flood in the basement could overload a system.
3. The drains in the basement are normally draining out to daylight, or to a drywell, if the sewer would back up the drain in the basement it would back up there first
4. All basement floor drains to sewer systems I have encountered have a plastic ball built into them to act as a check valve to prevent backups from occurring. I would imagine the ball prevents sewer gasses from entering also. No water is necessary to maintain it's integrity.
5. If an older home they maybe joined into the storm and you would have no sewer gas
6. nothing. get a gas mask
7. If you live in an urban area, there may be a house trap just before your building drain ties into the main sewer. That would keep a lot of the stink out.
8. if they are like most houses and mine the floor drain has a plug in the side of the drain, a small amount of water can go to the drain and be caught in a pipe about a12 or so inches in length and evaporate over time, removing the plug will allow any stopped sewer line to back up to the floor drain, especially if it the main sewer line that is blocked, i know because my plug was removed and the washer had plugged the main line and water was coming up the floor drain
9. Water will evaporate over a period of weeks. Instead of water use mineral oil. It will take a long time for the mineral oil to get out of the trap. Best of luck.