Bad Odor Downstairs

[drei]

Help!

When the upstairs toilet/shower are used, the downstairs bathroom directly below it smells. The house is 14 years old and there hasn't been any construction. There is no septic tank here. There is a vent/fan for each bathroom.

This is a new problem. The sewer smell isn't there unless the upstairs bathroom is used.

What would be the first thing to check?

 

[Doherty Plumbing]

Help!

When the upstairs toilet/shower are used, the downstairs bathroom directly below it smells. The house is 14 years old and there hasn't been any construction. There is no septic tank here. There is a vent/fan for each bathroom.

This is a new problem. The sewer smell isn't there unless the upstairs bathroom is used.

What would be the first thing to check?

Perhaps a floor drain trap has run dry.

If not you may need to have the venting snaked as a trap may be getting siphoned dry.

 

[Sponsor]

 

[Frenchie]

My first thought is that the downstairs or tub trap is getting emptied by negative pressure. Check the upstairs toilet's venting.



edit - Doherty beat me to it...

 

[hj]

odor

A siphoned trap in the upstairs bath would not give odors downstairs. If the downstairs fixtures, especially if there is a tub or shower, is not used fairly frequently its trap will dry out and give those symptoms.