Smell under Kitchen Sink!


Hi all
Can I pick your brains please?
I have an awful smell under my kitchen sink.
I have been told that it is a 'foul soapy water' smell!
I have taken all the waste pipes out and washed them in Bleach along with flushing out the overflows.
I have also taken 'jet washed' the outside drain and the pipe leading to that drain.
I have taken the cupboard walls out and washed the actual kitchen walls behind the cupboard.
All of the waste pipes were semi clean with no offensive smell.
I have also looked under the cupboard and washed the floor.
So now all I have is a wrecked cupboard, sparkling clean pipes and a very, very bad smell!
The only other thing in the cupboard is my waste disposal unit, which is sealed.
When I took the waste pipes off they were cleanish and I smelt the pipes leading from the waste disposal and they were fine, There is no smell coming up through the sink drains, only when you open the cupboard door.
I have given up! even my builder doesn't know where the smell is coming from, any ideas?
Thanks Denise
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Pinkypinx wrote:

Suspect the mechanical vent if you have one.
MM
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Hi Mark do you mean the mechanical vent on the waste disposal?
Thanks Denise

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Pinkypinx wrote:

You have a mechanical vent if your disposer and the other sink drain into a P-trap, which in turn drains into a Tee fitting. Screwed into the Tee is a white or black gizmo - the mechanical vent. The bottom of the tee is the drain going vertically through the bottom of your cabinet. If your P-trap drains horizontally into the wall you don't have a mechanical vent.
MM

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Also known as an Air Admittance Valve is supposed to let air into the pipe but not out. These are often buried inside of the wall and should be positioned above the flood level of the sink (not under it, but might be anyway)

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Like the smell I get from leaving dirty dishes in a sink full of water for a week.
Sounds like you have a mold problem. Some molds are harmless, some can make you sick and some just plain stink. Maybe you have a dead rodent inside the floor, it will go away soon enough. Do you use rat poison by any chance?
If you had an undetected leak for a while and the cabinet was allowed to remain moist for a period, than you have a high probability of mold or mildew. Start with normal products for this from the supermarket or have it tested for mold. If it is black mold, you want to deal with it ASAP before it spreads to other parts of the house or makes you sick. ( I have a friend who almost died from a bad black mold infestation and still suffers neurological symptoms)
You could also check your dishwasher connection, you may have a lump of rotten gunk inside and it is outgassing through the air gap (that thing that looks like a broken soap dispenser on top of the sink, if you have one, some areas allowed direct connection of the DW to the garbage disposer etc)
In any case, if there is no smell in the pipe, it is not a plumbing problem.

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Denise:
In my previous home I had the same problem in locating the source of the smell under the kitchen sink. In my case, it turned out to be a crack in the ABS drain piping in the crawlspace under the house. Since the house was located in the San Francisco area, the leak might have resulted from one of the small earthquakes we had every few years. I had to crawl under the house and replace the trap and adjoining pipe. The ground was soaked with smelly waste and small fruit flies were circling. Fortunately, there was no termite damage. When the soil dried out, the smell disappeared.
Goodluck, Keybored

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do we eat a lot of fruit fly eggs or larvi or what????

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