Sewer gas in basement

[jae]

Weird problem. I get sewer gas in my basement when my washing machine (on 1st floor) drains and spins. The smell seems to be coming out of the floor drain. Really old house/plumbing. Built in 1909. Other than when that washing machine drains, I never get sewer gas down there. Thoughts?

 

[pasadena_commut]

Not quite the same thing, but perhaps have a quick read through this recent thread:

https://www.plumbingforums.com/threads/persistent-sewer-odor-in-my-basement-driving-me-crazy.26397/

My first thought is that there may be a partial obstruction in your house's sewer line. When the washing machine runs it dumps a lot of water very fast, which backs up from the obstruction, and that is enough in this case to push sewer gas back through the trap. Kind of like how a toilet will bubble (or overflow) when there is an obstruction in a common drain line and the tub is emptied.

Does the washing machine empty into a sink? If so you should be able to reproduce the problem by filling the sink then pulling the stopper. Warning, that might push in enough water to overflow back out of the drain, so be ready to put the stopper back in.

Is there a plate in the basement that seals a clean out? If so, rootering the line from that point may be the next step.

 

[sawsaw]

k

Weird problem. I get sewer gas in my basement when my washing machine (on 1st floor) drains and spins. The smell seems to be coming out of the floor drain. Really old house/plumbing. Built in 1909. Other than when that washing machine drains, I never get sewer gas down there. Thoughts?

Just a thought ... are you sure you are smelling sewer gas and not a rotten egg smell. That would relate to your water heater

 

[jae]

k

Just a thought ... are you sure you are smelling sewer gas and not a rotten egg smell. That would relate to your water heater

no, it's definitely sewer gas. I've had plumbers down there watching/smelling what happens when my upstairs washing machine drains....as soon as it starts draining, the sewer gas smell comes up through the floor drain. Waiting on them to coordinate with a roto rooter guy that has a camera. I live in small town Indiana and it's hard to find good plumbers/contractors....ugh. I appreciate the reply, though

 

[GReynolds929]

Sounds like the trap is being siphoned maybe, or is already dry. Modern washing machines pump a higher volume of water at once, which means a bigger slug of water is flowing through the drain past the floor drain piping.