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I noticed that when my washer drains, the toilet bowl in my laundry room bubbles from the displaced air in the sewer line. No, the sewer line isn't clogged, I've checked. This sometimes siphons all the water out of the toilet bowl, allowing sewer gases to escape until I next flush the toilet to refill the bowl and reestablish the water seal.

This toilet isn't the lowest sewer connection in the house - I have a drain in my basement that's lower and doesnt run into any siphoning issues. None of my toilets on higher floors exhibit this issue.

Any idea what's causing this or how to prevent it?

I noticed that when my washer drains, the toilet bowl in my laundry room bubbles from the displaced air in the sewer line. No, the sewer line isn't clogged, I've checked. This sometimes siphons all the water out of the toilet bowl, allowing sewer gases to escape until I next flush the toilet to refill the bowl and reestablish the water seal. This toilet isn't the lowest sewer connection in the house - I have a drain in my basement that's lower and doesnt run into any siphoning issues. None of my toilets on higher floors exhibit this issue. Any idea what's causing this or how to prevent it?

(post is archived)

[+] [deleted] • 4 pts
[–] • 4 pts

You have a blockage at the end of your sewer/septic line. The vacuum created as your washer water exits the system activates a “flush” on your toilet.

[–] • 2 pts

I know someone that had a similar issue and this was the cause. YMMV though.

[–] • 3 pts

one of your vent risers is clogged with something.

[–] • 1 pt

As others have said, you have a vent blockage. This is not a clog issue down the line, it is insufficient air admittance.

[–] • 1 pt

That makes sense. I scoped the sewer line (all good), but didnt think to check the riser.

[–] • 0 pt

Please let us know what your end result and solution is!

[–] • 1 pt

Make sure you don't have kikel sewer rats trying to climb through the drains.

[–] • 1 pt

My sewer line is upwards of 100' long, if a sewer rat climbs it I'm giving it a Shawshank medal for sheer perseverance.

[–] • 0 pt

Do you have an air gap where your washer drains or is it directly plumbed into the drain?

[–] • 1 pt

There's a small air gap. I hadn't considered plumbing it directly, that seems like it'd be a noisy mess that'd drain about as poorly as modern gas cans.

[–] • 0 pt

It is good it has an air gap. I was thinking lack of one could be the problem.