2nd floor drains have sewer smell

pistolkell

This is on my second floor. Left drain is connected to my furnace and has rusty looking water and right drain is connected to hot water tank and doesn't have water and sewer smell is coming from that, what should I do? I've had leaks from these drains which ended up leaking on my first floor so I didn't want to add water without asking for opinions

VIPlumber

Odd that toilet flanges were used. But that's not really the issue. Do you know if there is a P trap in both lines? The problem that I see with this set-up is that even if there's a trap, as these are not regularly used/high use drains, the water will evaporate eventually and allow sewer gases back into the house. You may need to inspect monthly and fill with water as required.

pistolkell

Thanks for the reply. know there is a trap on one maybe both. So should I add water to the drain where there is no water visible? Can that cause a back up or overflow? And how much do I add?

TheEplumber

I would add a couple of glasses of water to the one on the right. More would be fine but you said you've had leaks on the 1st floor ceiling. a couple glasses should be enough to create a trap seal.


On a side note, a lot of plumbers in my area do this same set up- using flanges with 3 x 2 reducers. When the equipment is in the garage, they are pipe directly out the joist bay to the exterior. No trap is then needed since it is not connected to the sanitary drain system.

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