Vinnie, are you sure this is the problem? I read that paper you referred to and it doesn't mention anything about odors. The reason I'm asking is because I have the same odor problem in my home. I live in Toronto.

Ian9,
You piggybacked on a three year old thread so I gave you one of your own. Describe the smell. Where is it the strongest? Give us some details we can work with here. Regards, Tom

Here's how I describe it: A mix between chlorine and a metallic smell? It comes from the basement up through the air ducts. When the HVAC fan is on, it is worse. Some days, depending I think on ambient weather conditions, like air pressure and temperature, it's worse. Our house is 17 yrs old and was built very air tight, so I suspect that a low pressure situation gets created in the house compared to the drains and sucks drain air in, but I can't be sure. Also, the basement is rarely used so taps and toiler down there don't get used much. I think this summarizes the symptomatic details. I'd appreciate any ideas. Thanks so much.

the basement is rarely used so taps and toiler down there don't get used much. And I think you just solved your problem. I would go down there and fiull any unused trap, including the floor drain, with cooking oil. If the toilet's unused I would shut the water off to the tank and drain it. I would then pour a gallon of Anti-Freeze in the bowl. I think your odor night be coming from traps that have evaporated allowing sewer gas to pass. Good luck, Tom

Are you saying the I should put cooking oil in the traps because it doesn't evaporate? Is there any downside to that?

Are you saying the I should put cooking oil in the traps because it doesn't evaporate? Is there any downside to that?

The only downside that I can see is that the cooking oil can't be reused. LOL Tom

Unless I want to make french fries in the trap. Thank you for your generous advice Tom! Have a great day!