I have the same problem. Discovered it was the drain attached to the disposal that leaked all the mashed up food under my house in the crawl space. We have since fixed the drain, but do not know how to get rid of the garbage that is laying in the crawl space. Can anyone give me some suggestions? Thanks

Apple Blossom, I did not forget you. I continued to treat the odor but no good. So I replaced the Disposal, because I noticed that it was rusty inside. I then found garbage left in the drain hose from the dishwasher to the disposal. My wife has used the dishwasher once in 2 years we live here. Also she hardly ever uses the disposal. This has caused a build up in the hose and the hose itself was causing the odor. Even though I had cleaned the inside of the hose with bleach, the black rubber had kept the odor. I pulled out the hose and the odor has diminished to very very light. I am in the process of airing out the cabinets and replacing the hose and asked her to run the disposal and the dishwasher at least every two weeks. If you don't here from me, this was the fix. Tony

Could it be possible that some food particles have lodged in the trap and are now starting to smell?

Remove the trap and remove any material.

Lotta (Nick),
"Could it be possible that some food particles have lodged in the trap and are now starting to smell?"

It's doubtful that any food has lodged in the trap. "P" traps are designed to be selfscouring to prevent that very thing. Since Apple Blossom has tried every thing in the book I wonder if there was a spill that soaked into the cabinet floor and now the smell's part of the cabinet floor. What are your thoughts on this? Tom

I have this same problem and found this site searching for an answer. I have a weird odor coming from under my kitchen sink which is in a bar also. It is very strong when you open the doors. We have checked everything, had the plumber come out and have run out of ideas.

My friends and family say it smells kind of chemically yet not quite like any chemical we know. Our house is brand new.

I was told if I have an AAV then the smell will never go away. It smells kind like rank water but not like dead flesh or rotting food. Its really hard to describe. It makes me nauseous (I am a little sensitive to strong odors) and I will do just about anything to get rid of it. If we make the vent go down under the floor to the crawlspace can the gases escape like they should?

I hope I can find some answers here!

Hey Gal,

"I was told if I have an AAV then the smell will never go away. It smells kind like rank water but not like dead flesh or rotting food"

Not so if the AAV's working. However, if the AAV won't allow the spring to close off the vent you could get sewer gas back in you cabinet. To check this replace the AAV or remove it and cap the vent and see if the smell diminishes? Don't forget to replace it. Good luck, Tom

]I have noticed an odor coming from the cabinets where the kitchen sink is. I have looked for any leaks where the sink is, but have not found any. Could the odor be coming from the sewage? How can I tell? If so, then what can I do to get rid of it? Any help would be a appreciated. Thanks

I had a sewer odor under my kitchen sink, 3year old house, sink in a island, with dish washer and disposal. No leaks, disposal clean, AAV good. A plastic hose supplied with the dish washer ran from the washer to under sink and it ran into a rubber hose and it ran to the disposal.
The odor was coming from the rubber hose. The odor over time had penetrated the rubber. The hose looked new on the out side. The washer maker supplied a plastic hose for a reason. Don't use rubber under sink.

This site is great – thanks. I’ve read the string, and am facing the same problem. Did anyone arrive at a conclusion? I have a smell under the kitchen sink that one handyman called sewer gas, and another suggested it was rotting wood. I have no idea how to distinguish the two, it could be either, I suppose. It’s bad. It’s not a dead animal. The smell must be a long term thing, because the previous owners cut a hole in the cabinet floor to the slab, and it’s dry concrete. The wood looks like it was soaked at one point, and then dried, but the smell seems to come from everywhere in the cabinet, and from the adjoining cabinet between the sink and the dishwasher. The dishwasher has a sort of mildewy smell inside it, but it doesn’t really have that smell that the cabinets do, and it's only from inside the dishwasher. The smell doesn’t seem to come from the dishwasher space or from behind the dishwasher, as far as I can tell. It doesn't come from the sink itself. My father in law had earlier said that my roof vent must be clogged because of the weak flush in the toilets on the other side of the house, and then a handyman now said it must be causing this smell, but I’m skeptical. How could that work? Wouldn't the smell come from the sink, then? (I’ll look at the vent tomorrow, either way). For what it’s worth, there seem to be ants coming from that area between the two cabinets every now and again. Because it’s dry below the cabinets, I suppose I’ll just spray it with Killz2 and hope for the best, but what do you all think?

I am another person with the bad odor in the cabinets under my kitchen sink. Had our septic cleaned today thinking maybe that had something to do with it although they said probably not. It's not coming from the sink, drain or disposer. Just a rancid ever-present smell under there that started about a month ago. I've tried baking soda, charcoal, and some stuff I bought over the internet. Nothing will get rid of the smell. Anyone else have any luck in finding the source and a cure?

I have a mildew odor coming from the sink drain side that has the garbage disposal on it. I have tried baking soda, bleach and squeezing lime juice in it. It does not come up from the other side of our sink (double sink) and not through any other drains in our house. Is there a way of getting rid of this constant odor?

I found out what the odor was under my kitchen sink. I actually did research on this as well and found online what the possible issue was. The smell was coming from the hose that connects from my dishwasher to the garbage disposal. I guess it wasn't installed properly (basically was too long and had a U shape) Water was being left behind in the U shape and basically was smelling through the rubber hose. I took the hose out and almost puked with the smell of the water as well as the hose. From the outside the hose looked new but inside it was pretty bad and brittle. Long story short, I have replaced it using a shorter hose that flows nicely to the garbage disposal. So far I had to air out the cabinet under my sink but it's safe to say the odor has disappeared. I hope this helps.

Handyman619: thank you for verifying what we have been talking about here for some time.

However, D/W hose always has U in it. If you don't use D/W for several days, dirty water with food residue will rot and vent the smell out of air-gap or g/d. I cannot imagine how you installed new hose w/o U in it. If you put it straight to g/d than leftovers from g/d will potentially overflow into d/w hose and clog it.

As above, I live in a 4-year old home and last summer began having bad odor under sink in kitchen cabinet. Winter it seemed to decrease significantly, but this summer is much worse than last summer. Before going to the bother and $'s of all those preceding me, I am trying all the lesser "invasive" procedures. Roof vent is clear, no leaks in wall or under cabinet, plumbing appears correct, do have 1 rubber tube from overflow vent at top of sink to disposal, tubes/pipes are clear. We run disposal daily and dishwasher about every 2 to 3 days. One factor?? is my husband and I teach so do not run dishwasher and disposal as often during school year but more in summer. No odor from sink above. Removed rubber hose over night, covering disposal w/heavy plastic and towel and more plastic, and smell was worse in morning. No leaks from past or drainage issues. Sometimes I do have to turn on the garbage disposal a second or two if dishwasher is running, as a little water backs up, but this is infrequent. Anything anyone can add beyond the above scripts?

I have two upstairs bathrooms that smell ONLY coming when the door(s) or drawers open
Drilled 4" hole in the bottom of the undersink closet and all is clean and dry!

The sewer pipe leaves through the wall.

I think that behind the wall is the connection with the vent pipe that goes to the attic and then roof. Once the sink was clogged and the plumber cut this vent pipe in the attic to rooter the clog out. He told me that the cause was the AC drained into this pipe (against code)

I am going to open the wall to see if the connection between vent and sewer pipe, or vent pipe itself is an opening that leaks gas, but am afraid that it could be very small and not visible

EdBill, after more than a year, we do believe we solved our problem. Although the smell was worse when we disconnected the rubber hose, took it out, and covered the holes with rags and duct tape for 2 days, we decided to totally replace it anyway with a vinyl plumbing hose to really know. We couldn't quite get the exact size inside diameter but close and used worm clamps. The next day the smell was less and the next even less. That lasted about 10 days and we assume it was just in the wood of the cabinet. I set a strongly scented unlit candle under the cabinet for a week and removed a week ago. The bad odor is completely gone. Thanks to everyone above with their trials and errors because we likely would have done the same.

EdBill... Oops... unfortunately, it sounds like your problem is a different one with your possible changes in the venting.

I hope I found the problem I mentioned earlier in my upstairs bathroom
I already had the suspected that the vent pipe was the problem, because the AC drain is using it as a drainpipe (not according to code, 1960's house)

So I filled both sinks with water and opened both... and water drained very very slow, because the "vent" didn't supply the necessary air... vent pipes suck air, not the other way

Tomorrow I will cut the vent pipe in the attic and try first with power powder solution from the pool to kill all the algea before using a snake

Hope this will work, because when I put some chlorox down th Ac drain, I didn't smell so much for some time

EdBill, before you cut any vents in your attic, check pop-up assembly for body hair. Yes, Code doesn't allow A/C condensation line to drain into vents anymore - however it has almost no impact on your 2 slow draining hand sinks. It only distracts you from locating the real source of your drainage problem.

Vents play important role in overall plumbing system. However, it takes lot more for vent to prevent 2 small hand sinks from draining. There is enough air in the "clogged" vent to drain your sinks. Look for problem in your sink drains...

Thanks Milo, you are right. I did it. A month ago I replaced both faucets and pop-up's and cleaned the traps.
I just cut the iron pipe, and put very concentrated chlorine in, but just in case I put a snake a couple of times in and out, and picked up some yuck, yellow white, maybe colored by the chlorine, then poured a lot chlorine in to rinse and closed the pipe with a rubber connector and two clamps.
Filled both sinks and they now drained pretty fast with a good gurgling sound.
I have closed the cabinets and will check tomorrow if there still is a smell
But... if the smell is gone then this should be the problem, but... that means there must be a hole, tiny maybe, but a hole somewhere in the vent pipe or connection that only leaks gas when the inside pipe pressure is a little higher then under the cabinets. I am still puzzled about this