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Summer Only Sewer Smell

As the title of this thread suggests, we have an issue with sewer smell, but only in summer. I'm pretty certain it isn't caused by dry traps as the traps are flushed more in summer than any other time due to more showers, more laundry, etc. We haven't smoke/peppermint tested the vent yet because my gut tells me if it was the vent, it would happen at least once in a while during other seasons. As it is, it only happens occasionally, say two or three times during the summer. I'm wondering if the problem could be from our home's proximity to the sewage plant in our town and if so, if there is anything that can be done about it. There is our home, next to ours another and then next to that an apartment complex. After that, a 2 lane highway and then just on the other side of the highway, the treatment plant.

I know that might sound odd, but if this were a dry trap or bad vent situation, wouldn't this be a problem year round? In summer (obviously) raw sewage is going to smell worse. I have actually been able to smell it outdoors on a couple of occasions, and both times, I smelled it in the house first and then noticed it when I went outside. I dont' always smell it outside when it is happening inside though. I'm just wondering with our home being so close to the end of the line if it is possible that this is the cause. Any thoughts?

Re: Summer Only Sewer Smell

A couple possibilities....

It could be a "draft" coming from the treatment plant. There is a plant in the town near us that sends an odor to a specific part of town about 3/4 mile away. The breeze follows a creek from the plant to the town. You may have a similar situation. Have you traveled toward the sewer plant to see if the smell matches? For one of my jobs, I sell equipment to sewer plants and some have a specific odor to them based on the type of processing they do.

It could be that there is not a good breeze on the days you get the smell and it is coming from your vent stack. The odor hangs around rather than being carried away. On those days, maybe you could get on the roof at your vent and see if it is more concentrated there.

You may have a bad wax seal on a toilet that is allowing the gas to back up, but is not so bad to cause a severe water leak. This would explain the smell inside, but probably not outside.

Hope this helps.

Re: Summer Only Sewer Smell

Thanks for the ideas! Wax gaskets have been replaced on both toilets recently so that likely isn't it. I suppose I should have been more specific and stated that the sewer smell we sometimes have indoors always originates in the laundry room (the vent pipe passes through this room) and on occasion has been bad enough to permeate the entire house. More often than not, when the odor is apparent inside the house, you can't smell anything outside. My husband thinks (as you have suggested) that it has a good deal to do with wind direction. If that's the case, I suppose there is nothing to be done for it. Fortunately, it doesn't happen often, but we're remodeling with the hope of selling and it is my thought that a potential buyer will be put off if they come in to look and smell raw sewage!

Thanks again for your input.

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