Odor under kitchen sink

There is a very unpleasant smell under my kitchen sink. It smells acrid, something like pet urine or a lemon that has decayed. I've removed everything from the cabinet and cleaned the cabinet with vinegar, baking soda, etc. to no avail.

There is no smell in the dishwasher, disposal, or the sink drain hole. There are no leaks under the sink and everything - disposal, dishwasher, drain - works fine.

I went in the crawlspace and looked all around the area under and by the sink - no dead animals, no water leakage, no rodent feces.

Then I put mouse traps in the cabinet and the dishwasher, thinking something could be living in there, but neither trap was sprung.

I talked with 3 plumbers who all said it wasn't a plumbing problem and they didn't want to waste my money. One suggested I start cutting holes in the bottom of the kitchen cabinet - and maybe the back wall as well - to see if something is in there.

This is a 20-year-old Kohler sink and nothing new has been added to the plumbing in at least 10 years.

Short of tearing out my kitchen cabinet, does anyone have any ideas? I've looked online and it looks as if others have had this problem, but I don't see a post about how it was resolved!

One note, I don't have any gas appliances in my kitchen, so that's not the source of the problem. Plus, it doesn't smell like gas.

Thanks for any help you can provide!

how old is the disposal? does it have something wrapped around the middle of it for noise? i have had older disposals corrode through under the outer cover and when you use it little bits of garbage are thrown into the space behind the outer cover. they dont always leak enough to be noticed.

Thanks! It's a 20-year-old Maytag. I don't know about "wrapping" but it has a thick black (plastic?) band running around the middle of the unit. It's where the discharge hose comes out. I tried to see if that area smells worse than the rest of the cabinet but the overall smell is so bad that I can't tell!

Way past time for a new disposal. Moving metal parts constantly exposed to water don't last forever. It would be a waste of time and money to even attempt a repair.

Did you perhaps have a container of Pine-Sol or similar smelly product stored under
the sink which perhaps leaked and soaked into the wood? To me, "rotting lemons" pretty
much describes the odor of Pine-Sol, which lingers just about forever.

Drilling 5 or 6 holes in the cabinet base is a way to test the under-cabinet space. It lets air out and this will give you a sense whether or not there is a stronger odor coming from there or not.

Can you remove the kickplate cover? Underneath the sink cabinet is a 3" space. You haven't looked in there. You haven't even mentioned it.

Drilling 5 or 6 holes in the kickplate cover is another way to test the under-cabinet space. It lets air out and this will give you a sense whether or not there is a stronger odor coming from there or not.

Later, it is easy to close the holes.

Have you emptied the cabinet entirely?

I've decided to replace the disposal tomorrow, so I'll let you know if that's the source of the smell. It's not that expensive to replace and it sounds as if it's time.
If that doesn't take care of the smell, then I'll start opening up the cabinet floor and back panel ...

Thx!

No, no PineSol or anything else, but thanks for the feedback!

Someone else also suggested cutting a hole in the cabinet floor and then repairing it just the way you would a drywall repair. And maybe do the same thing to the back panel of the cabinet. But when I was in the crawlspace, right below the cabinet, I couldn't smell anything.

The cabinet is completely empty and I've cleaned it several times. The disposal comes out tomorrow and if that doesn't fix the problem, I'll have saws and drills nearby ...

Thanks for your feedback!

outside the DW, this an inch of space on both sides.
The DW is not in a cabinet, but squeezed between two cabinets.

It is usually easy to slide the DW out a few inches and look to the two back corners.
With a flashlight you might find the dead mouse you have behind the cabinet.

Odor mystery solved

OK. The repair guy took off the dishwasher kick plate and found nada. Then I had him put in a new disposal, but the odor was still there. So then he punched a few holes in the sink cabinet floor but didn't see anything nor smell anything. A friend came by later today and pulled off the cabinet kickplate and found mouse droppings towards the back of the cabinet, near where the pipes exit.

So no bad disposal, no dead mice trapped behind the dishwasher, just live mice visiting under the kitchen sink cabinet. Now to figure out how they're getting in and stop them.

I guess the reason the smell was like a chemical or urine is because that's what it is!

Thanks to everyone who came up with suggestions.