Sewer odor in upstairs bathroom after using kitchen sink/dishwasher situated directly under on the next floor down

[Majesty-2030]

Why would using our kitchen sink or dishwasher cause this odor in upstairs bathroom?

In the kitchen, there is a double sink, with a dishwasher connected to a garbage disposal, on the drain to the right, and an AAV on the drain to the left.

No odor on the level with the kitchen when using sink or dishwasher.

There’s water in the traps of bathroom fixtures upstairs (no siphoning). The AAVs in the kitchen and bathroom have been replaced. There’s no clogged drains in kitchen or bathroom. I’ve used Bio-cleaner, a powder bacteria drain cleaner, on all drains to no avail.

 

[WorthFlorida]

Is this something new?

As water drains the air in front of it is being pushed causing a slight increase in pressure. It has no where to go so it is pushed through and out the bathroom trap. AAV is a one way check valve, it only lets air in. Somewhere in the home is a roof vent. You must check the vent that it is not clogged. May have to run a garden hose down the vent pipe.

At the Kitchen sink AAV, check that the elbow into the wall is not blocked with crud. Tape up the bathroom sink drain and overflow and add water to seal it up. It's to be sure that it is the sink and not the tub or shower.

 

[Sponsor]

 

[John Gayewski]

Whomever piped under your kitchen sink did some odd things. That said I don't know why your problem is happening, but try removing an aav for a while and see if that fixes the issue. You have to eliminate one thing at a time to see what's happening. Another thing you could try is watch and listen to the upstairs fixtures and see if they burp out any air.

 

[WorthFlorida]

Whomever piped under your kitchen sink did some odd things. That said I don't know why your problem is happening, but try removing an aav for a while and see if that fixes the issue. You have to eliminate one thing at a time to see what's happening. Another thing you could try is watch and listen to the upstairs fixtures and see if they burp out any air.

Agree, the AAV connection needs to be above the trap arm of the sink. It appears that another drain that was used for a double sink.

 

[Majesty-2030]

The problem is resolved. I had the drain on the left capped, and added an AAV above the trap on the drain to the right. Not sure how that fixed things, but it did! Thank you both for the advice!

 

[WorthFlorida]

The problem is resolved. I had the drain on the left capped, and added an AAV above the trap on the drain to the right. Not sure how that fixed things, but it did! Thank you both for the advice!

Thank you for the update.

 

[Caliber_Plumbing]

The problem is resolved. I had the drain on the left capped, and added an AAV above the trap on the drain to the right. Not sure how that fixed things, but it did! Thank you both for the advice!

Good to hear that!