My moms house recently started to reek like sour rotting cabbage. We thought that is was just some dried drains in the downstairs bathroom that is rarely used. So we did venerate and baking soda, then let bleach sit for two hours before flushing with hot water.
The smell is horrible still! No one can identify where it originates from.
The house is 50 years old, however the kitchen and basement bathrooms have newer plumbing.
We have also had a large snowfall, I thought the vent might have gotten blocked on the roof, but it hasn't.
I'm at my wits end! I'm also very concerned that there might be some effect on my moms health, I get nauseated just walking in there!!

Hi LL

What kind of boiler/furnace system do you have?

If you have a forced air system then I would start to look at the condensate drain, the pan around the unit, etc...

Could be an issue at the furnace blowing the odor throughout the house or areas of the house.

It is forced air, I have no idea what models they are! Thanks for the reply, I will check it out and let you know.

It is forced air, I have no idea what models they are! Thanks for the reply, I will check it out and let you know.
That doesn't seem to be the culprit either. We're going to pull the fridge out and clean the tray underneath today. I'm really hoping to solve this mystery so my mom isn't spending any more money. She has a fixed income. I appreciate any more suggestions as well.

Check to see that the furnace is producing condensate and that the condensate pump is pumping. If the condensate pump doesn't pump on occasion then the codensate line is plugged and backing up into the furnace... can create quite a stink... ;)

Only other thought is a dead animal in the walls... can also create quite a stink!

I took apart the humidified tray and filter and cleaned everything, there was a lot of mineral and calcium deposit to scrape off. When I replaced everyone and turned everything back on I realized the motor wasn't working. Could that have caused the stench?

The motor is the blower motor... may just need to press a RESET BUTTON (look for it) to resolve that issue!

In terms of the odor, a burnt motor could cause a burn smell, not a "sour cabbage" smell you mention, OK?

Did you check out the condensate pump and check to see if condensate water is getting discharge into the pump and then pumped up and out? At this point, this still seems the likely culprit to me? Do you know what and where the condensate pump is?

The condensate pump is fine. The motor that's not working is the one that spins the filter. I didn't see a reset button on that one. My mom is going to call the furnace company on Monday to see if there's still some warranty left.

Hmm... keep me posted if you have a chance, OK? Thanks! Mark

Hmm...keep me posted if you have a chance, OK? Thanks! Mark

I will Mark! Thank you for your help, I really appreciate it. My mom was out for half the day and then home. She said the smell isn't nearly as strong. Maybe it's just taking time for the smell to dissipate.
Thanks again!
Christine

It turns out that it was the humidifier and a dry P trap. Because the motor wasn't spinning the filter water in the tray was stagnant. As soon as the heat would turn on it would blow the gross smell all over the house. Plus the shower drain in the basement, that smell lingered for a few days after I cleaned it. Thanks for your help! We shut the water off to the humidifier until it gets replaced early next week. The house smells a million times better now!

Thanks for the update... always appreciated!