crawl space onion smell

JHinCA · #1 09/22/10, 08:10 PM

There is a small cottage on our property with a shaky septic system that has not been used for months. When walking by there I have noticed a smell of rotting onions and thought it was the neighbor's compost pile. I investigated further today and it is not compost, but is coming from the crawl space under the cottage. Any ideas what this might be? It has been the same smell for a long time so any specific thing that was rotting should be gone by now. My first thought is the questionable septic tank, but this is not a septic kind of smell at all and there doesn't seem to be any dampness around.

Any thoughts?

Jean

donewithcity · #2 09/23/10, 01:14 AM

In urban Los Angeles, I found a possum nest under my Dad's house. Get down there and look around. Spooky? Yes. But Once you have toured the subterranean part of your residence, you will feel much better.

donewithcity · #3 09/23/10, 01:20 AM

BTW- if you suspect a gas leak - In any form, a minute amount of odorant such as t-butyl mercaptan, with a rotting-cabbage-like smell, is added to the otherwise colorless and almost odorless gas, so that leaks can be detected before a fire or explosion occurs

jennigrey · #4 09/23/10, 02:48 AM

I have found that at least one kind of snail that is indigenous to my area smells strongly of garlic/onion when it is bothered. There are a few areas around my barn and house that pretty much always have that odor. DH's nose doesn't work the same as mine does; he can't smell it. Lucky him!

**Cabin Fever** · #5 09/23/10, 08:14 AM

Cat whiz

DamnearaFarm · #6 09/23/10, 10:24 AM

Really, CF? Onion smell? I hadn't thought of that.

That's funny. There's a particular bush/shrub that grows around here, don't know the name, but I refer to it as the Cat Pee Bush. That's exactly what it smells like to me!

We'll just not get into what Bradford Pears smell like.......

Ardie/WI · #7 09/23/10, 10:31 AM

Quote:

Originally Posted by Cabin Fever

Cat whiz

That's what I thought of too, although it's a wee bit different in odor.

Harry Chickpea · #8 09/23/10, 12:38 PM

Quote:

Originally Posted by JHinCA

There is a small cottage on our property with a shaky septic system that has not been used for months. When walking by there I have noticed a smell of rotting onions and thought it was the neighbor's compost pile. I investigated further today and it is not compost, but is coming from the crawl space under the cottage. Any ideas what this might be? It has been the same smell for a long time so any specific thing that was rotting should be gone by now. My first thought is the questionable septic tank, but this is not a septic kind of smell at all and there doesn't seem to be any dampness around.

Any thoughts?

Jean

Yep. The pipe from the toilet to the septic may have broken at some point, pushing the raw sewage into the soil under the cabin and excluding oxygen from part of the soil. The sewage and soil and lack of oxygen somehow created propanthiol, which degraded into stinky sulfide compounds. There is a similar smell when you dig up a failed sewer pipe in clay soil. (BTDT)

Cat pee is a lot more acrid.

**Cabin Fever** · #9 09/23/10, 12:52 PM

Quote:

Originally Posted by Harry Chickpea

Yep. The pipe from the toilet to the septic may have broken at some point, pushing the raw sewage into the soil under the cabin and excluding oxygen from part of the soil. The sewage and soil and lack of oxygen somehow created propanthiol, which degraded into stinky sulfide compounds. There is a similar smell when you dig up a failed sewer pipe in clay soil. (BTDT)

Cat pee is a lot more acrid.

I've smelled more sewage in my life then I'd ever want to admit to, and none of it ever smelled like onions or garlic.

JHinCA · #10 09/23/10, 01:24 PM

No gas or propane hookup near there at all. The snail theory is interesting. We do have snails, though I have never noticed any onion smell to them.

So far as I know there are no cats around, since our dog keeps them away. Could be the pee of some thing else, I guess, though it does not smell like either pee or sewage to me.

HC says "The sewage and soil and lack of oxygen somehow created propanthiol, which degraded into stinky sulfide compounds. There is a similar smell when you dig up a failed sewer pipe in clay soil. (BTDT)"

Our soil is heavy clay, so maybe it could be that. Wouldn't there be some dampness though? Wouldn't the smell go away after months of the septic not being used?

Thanks for the all responses. HT is great, no mater what weird question I ask, people have answers.

Harry Chickpea · #11 09/23/10, 03:05 PM

"I've smelled more sewage in my life then I'd ever want to admit to, and none of it ever smelled like onions or garlic. "

LOL! Guess I'm just lucky. FWIW, I'm convinced there is no "one size fits all" to scents, and that we each have somewhat unique "sniffers." Other folks like perfumes, I find a majority of them offensive. Other folks tell me that roses smell wonderful. I find the smell mild and not particularly exceptional. Some folks can't stand broccoli, others love it. The smell I'm thinking of is not one you get from opening a septic tank or a municipal operation. I've only smelled it in sewage saturated clay soil or muck.

I don't know about the smell going away or not. My experience with the strong smell was with a fairly localized problem.