Joe M]Hi speedball1,

I found you in a Google search I was doing this morning and you seem pretty knowledgeable about plumbing. Hoping you can help me with a question re. sewer gas. Ever since we put in a front load high efficiency washer, we smell sewer gas when using the machine. I'm guessing it's coming from the floor drain, but am perplexed at the cause. It seems to be related to the washer, but that could be coincidence. We never had the problem with the old washer (top load). Any thoughts?

Joe

Good morning Joe, ( I moved this post over from private messages)

I'm on Google? Does that mean I'm famous?
Different washers have different pumps and your new washer discharges with more force and volume then your old one did. I'll bet a cookie that if you listen to the floor drain while the washer's discharging you'll hear some "gurgling" and "bubbling" going on.
The usual cause of this is a partial blockage located down stream of the floor drain that will allow ordinary drainage to pass but when a high velocity hits the blockage it bounces back, sending a bubble of sewer gas ahead of it, before it drains on by. This "bubble" of gas is what you smell. The problem's repaired when you snake from the washer vent. Good luck, Tom

Just out of curiosity, is your trap primed by any means? That is to say, is there anything discharging into your floor drain now and then to make sure that the water in your floor drain's trap doesn't evaporate etc? If not then maybe there isn't enough water in your trap to create a seal. That might explain the sewer gas smell.

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Originally Posted by theBigkill

just out of curiosity, is your trap primed by any means? that is to say, is there anything discharging into your floor drain now and then to make sure that the water in your floor drain's trap doesnt evaporate etc? if not then maybe there isnt enough water in your trap to create a seal. that might explain the sewer gas smell.

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Big Kill makes a valid point. If the floor drain isn't used then pour a quart of cheap motor oil down the drain to replace the water in the trap. That way you'll never have to worry about evaporation causing sewer gas to escape. On the other hand if the floordrain's trap seal's intact follow my advice and snake out the drain from the washer vent. Good luck, Tom

Instead of motor oil, we've used peanut oil in our church's floor drain. A bit more expensive, but its probably more environmentally friendly and the peanut oil does not attract insects as other vegetable oils would do. Go figure.

Ron Gaus, St. Louis