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.

If you have a dishwasher next to it, check it for leaks. Make sure there is a trap in both the sink drain and dishwasher drain, the double "U" shaped thing where it goes down, turns, and turns and goes back down. The bottom turn should stay full of water, preventing sewer gas from coming up the drain.

If you can, check the crawl space below the sink, and see if there is any sign of a leak. Something could be leaking between the sink cabinet bottom and the floor. A mouse or rat could have gotten in there and died.

Could be a tough problem. Maybe somebody else will have another idea.

Hey Rusty, Labman gave you some great places to start looking. However all dishwashers discharge into one of two places. If you have a disposal it discharges into the opening provided for it and if no disposal then we install a "dishwasher branch" that replaces the tail piece from the kitchen sink drain. So you will always be trapped. Try this. Pour 1/2 gallon of bleach into your disposal,( if you have one, if not then down the sink drain) Let it set overnight next morning flush it out with a pan of boiling water. If you have a disposal, you can then cut a lemon into quarters and run it through the disposal. For a odor that originates from UNDER the cabinet I like Labmans sugestion. If you can, check the crawl space below the sink, and see if there is any sign of a leak. Something could be leaking between the sink cabinet bottom and the floor. A mouse or rat could have gotten in there and died. Good luck, Tom

I do not have a dish washer or a disposal. Have cleaned out the cabinets to see if something like mouse might have been there,but no signs of that. I think it is coming from sink pipes. I think it is sewer gases. Any idea how to fix this?

If the drain has the proper trap, and no leaks in the pipe, the sewer gas shouldn't be able to come out. It is possible some foul smelling material is sticking to the pipe above the trap. Try filling the sink with hot, soapy water and suddenly letting it out. Pouring boiling water down the drain might help. Some of you foaming drain cleaner might solve the problem too.

I have the same problem in my house. There is a very strong sewage smell coming from UNDER the sink. Opening the cabinet doors makes this very clear (juck).

Since the smell is coming from under the sink, it indicates to me that the problem has nothing to do with the sink itself.

It seems to me that this means that one of two things is happening:

1) An animal is dead in the wall. I don't think that's it, because it is smelly only under the sink cabinet. An animal could have died in any wall in the house. That doesn't eliminate this option of course, just make it less likely.

2) The smell is coming from a crack or leak in the pipe.

Going with option 2 as the most likely, and checking for leaks under the sink revealed nothing. However, the crack may be in the wall past the point where the pipe is visible.

I was thinking that one way of checking this would be to disconnect the pipes and cap that end of the pipe (just use duct tape) for a day. I don't want to get into tearing up the wall if I'm not sure.

Is there a way that sewage gasses could leak out if water doesn't leak out? There is no water leak under the sink.

Any other suggestions how the smell could originate from UNDER the sink?

You could very well have a leak in the lateral,(horizontal drain pipe) in the wall, and if your house is built on a slab, never see the moisture. It would seep out under the cabinet and just lay there and smell. If that's the case then capping off the pipe wouldn't stop the smell. I had the same problem myself when a copper pipe corroded through. I had to bust a concrete block wall from the outside to replace it with PVC. Just one suggestion. Tom

Hi Speedball1.

Yes, that is my fear, and capping the pipe should clear up whether it's in the wall or not. If the smell goes away, then it is not in the wall, if it persists, then it is in the wall. Here's my reasoning.

If the smell comes from a section of pipe that is in the wall, then after capping the pipe, the smell would still come through, because it is not going through the pipe, it is coming out somewhere in the wall.

If the smell has to do with the part under the sink, then capping the pipe will stop the smell, provided of course I flush everything with hot water first. Capping the pipe will stop the smell from coming into the area under the sink.

The area under your sink is called,(from the drain on through the wall) Basket strainer, tailpiece, trap,("J" bend) and the part the goes into the stubout is called the trap tail. If sewer gas were escaping from any one of those that would mean moisture could also get out. If running your hand from the sink to the wall didn't pick up any moisture then the cause of the smell is somewhere in the wall. While capping off the pipe would prevent fresh moisture from escaping that would still leave the liquid that is smelling up the place intact. It wouldn't just dry up overnight. There's a great difference between the rotting flesh smell of a dead critter, sewer gas and the smell of a leaky drain. You can tell the difference by sniffing the basket strainer and then sniffing under the cabinet. While it's possible you have a dead mouse under the cabinet floor my bet's on a leak in the wall. Do you have a basement where you can check for moisture or are you on a slab? Regards, Tom

I'm on the second floor, and there is no leak evident below. I'll run another thorough check for moisture under the sink (while running lots of water), and if I don't find any, I'll rip out the drywall to see where the pipe is going and if it's leaking in there.

If I do find a leak, should I take out a section of pipe and replace it, or can I use one of the pipe repair kits they sell at the hardware store? I think they basically involve some kind of contraption that wraps around the pipe and is tightened with a mechanical fastener.

Thanks for the help, I appreciate it.

If the pipe's ate up don't try to repair it. It will just leak again. When mine went it ate the bottom right out of a 1 1/2" type L copper pipe. I had to break a outside block wall to get to it. That was two years ago and I replaced the pipe that went from the stubout ell to the stack. This year the stubout went and I had to break into the wall again to replace it. Profit from my mistake. If you find a section of the lateral drain line bad, replace the whole arm and stubout with PVC. Good luck Tom

I am also having issues with smell coming out of my sink.

It is intermittent however and only seems to come out of the side where the garbage disposal is located. I plan on trying the bleach and lemon fix first but I wanted to know if anyone had any other suggestions.

Is there any reason it should be intermittent?

Kevin

I am also having issues with smell coming out of my sink.

It is intermittent however and only seems to come out of the side where the garbage disposal is located. I plan on trying the bleach and lemon fix first but I wanted to know if anyone had any other suggestions.

Is there any reason it should be intermittent?

Kevin


Hi Kevin,

Before the bleach and lemon flush the disposal out with a few pans of boiling water. That will loosen the grease and let the bleach do its work.
You ask, "Is there any reason it should be intermittent?"
Does it just stop dead for a second or two or does it hum when it stops?
Good luck, Tom

Hi Tom,

To be clear, the disposal doesn't stop just the smell.
I will flush with the boiling water first.

Since the smell's intermittent I probably won't know if it really worked for a week.

If there are any other suggestions please post.

Thanks.

Kevin

Wondering if an AAV might be the culprit? I have the same problem as some of the others on this thread. My house is just under 4 years old and this past summer we developed a nasty smell from under the kitchen sink. I've checked for leaks everywhere and there are none and I checked the only vent line that exits the roof and found no blockage. Since our sink is part of an island in the kitchen, there was no covenient way to run a vent line so the plumber used an AAV. Does anyone know if it's possible for an AAV to seep sewer gas? The device seems to be functioning properly as there is no sign of slow drainage. The smell seems to be more prevalent when it's humid outside, which only adds to the mystery. Any info would be greatly appreciated.

Hey Stew,

Since the AAV is a air vent you would see no water coming from it. Yes, it's very possible that a spring weakened in the unit allowing sewer gas to escape. I would change it out at the earliest. When it's humid outside the air's heavy and the sewer gas instead of raising to the ceiling stays low where you can smell it. Good luck, Tom

it's very possible that a spring weakened in the unit allowing sewer gas to escape. I would change it out at the earliest.

It seems as though there's a wide variety of AAV's on the market at varying price points. I'm assuming the one we currently have is on the cheaper side given the fact that it seems to have failed after only a few years... is there a particular brand that you recommend over others?

Hi Stew,
Yes, Studor Vents are manufactured just North of where I live. The nicest thing I can say about then is that I've never had to go back and change one that's gone bad. You may check them out at;
http://www.studor.com/homeowners.htm Good luck, Tom

I have the same problem and have tried the boiling water, etc without success. I called a plumber who came over but found nothing. I think I was ripped off though because he wasn't even going to check the trap until I suggested it. The smell is still there and it's been about three weeks now. What is an AAV? My sink is on a peninsula if that makes a difference. Thx.

What is an AAV? My sink is on a peninsula if that makes a difference. .

Hey Blossom,
You have a island sink with a AAV. A AAV, (Air Admittance Vent) is a spring loaded mechanical vent that replaces the need for a outside roof vent.
They are installed in island sink installations in place of a loop vent. Look under your cabinet for a thingy at the top of your drain line that looks like this. http://www.studor.com/homeowners.htm
If you smell sewer gas this could mean the spring in the AAV has loosened and isn't doing its job. Let me know what you find. Tom

Thanks Tom. I'll look tonight when I get home. FYI, my sink is on a peninsula and the plumber told me I have a vent pipe that goes up the short wall that anchors the peninsula. My sink cabinet angles out from that short wall. Do you still think I have an AAV? Thanks.

. Do you still think I have an AAV? Thanks.


You're the one that brought it up. Check it out and get back to me. Cheers, Tom

Tom, I don't see anything that looks like the AAV image you provided so that's not it. From previous research I did I thought the problem was sewer gases backing up possibly because the water to one toilet has been shut off for several weeks. The plumber said no, that's not the problem. He went up on my roof and said it's venting fine but when I asked him to explain how he could tell that he wouldn't say. Honestly, he acted like I was asking for the "company secrets". I'm quite frustrated. Today, another company is coming over to look for a dead critter. Thanks.

AppleBlossom let me know how you make out.
Tried the same methods, I even swapped AAV's with the Bathroom. I then Capped AAV. Called Plummer, he is convinced that it is not sewer gas. We looked under cabinet all dry and clean. Could be between cabinets in open space on angle of Island sink. Anyone know if you can get an inexpensive Flexible Scope with fiberoptic light to search for critters between the cabinets & walls? They have some expensive units on the net.

I spoke to another Plumber. He said I better cut open the cabinet and look for problems. Well I cut a hole in the side under the sink and NO PROBLEMS. Dry as a bone. No Critters and no bad smell. The problem is that the odor still comes from under the sink and we can't locate it. Any other suggestions.

"The problem is that the odor still comes from under the sink and we can't locate it."
TF,
"under the sink" Does that mean the smell is coming from under the sink in the cabinet area or from under the cabinet floor? Regards, Tom

Tom, the odor is in the cabinet area not under the cabinet. We checked under the cabinets and no smell and dry.

I should have asked. Is there a disposal involved? Tom

We have a new home that we moved into in June. It has a partial basement with sump pump. When the air was on, we noticed a faint smell coming from the dining room register. When the heat was turned on it got stronger. I covered up the register and the oder became strong in the kitchen. When I opened up the cabinet next to the Dishwasher it was very strong. It is kind of an earthy smell. We contacted the Heating people and they said it was not a mechanical problem (on the phone) and that we should have stanley steamer come out and check and clean out the ducts. New houses can have just about anything stuffed in them. This was done, $500 later and the smell is still there. We called out the Builder Customer Service guy and he admitted to an oder, but thinks it is the sump pump area. I wonder why the smell would be so strong in a kitchen cabinet, if it is a sump pump odor. We have checked under the dishwasher and see no evidence of moisture. There is a disposal that appears to have a tube running to the dishwasher. I smell nothing in the disposal. There also appears to be no odor from other registers.
Any ideas?

Hi Carole,

"It is kind of an earthy smell." Sure sounds liike a mold problem to me. If it were a drainage problem it would smell like sewer gas plus rotting food and plain sewer gas has a smell all its own. A sump pump smell would smell damp and heavy and, besides, the system is a closed one. Yours has somehow got into your air ducts and migrated to the cabinet in the kitchen. Very strange!
I keep coming back to--" Perhaps Stanley Steamer missed the spot the mold was growing in." Have you considered calling them back for a second look?
Please keep me in the loop and let me know what goes down. Good luck, Tom

Tom, yes I have a Disposal under the sink. The house is only 18 months old. The disposal was cleaned and no odor from below or above from the disposal. I called in a neighbor that use to work for the GAS Co. He said the odor is sewage. He had a lot of experience on natural Gas Calls and reconizes sewer odors. So I called back the Plumber and he will come next week and we will try to eliminate all the pipes and joints above the sewer drain by cutting a hole on the cabinet floor and cap off the sewer drain. Even though the AAV was replaced and also taped closed, I will feel better if we cap everything right down to the cement slab. I don't know what to do after this, any other ideas, let me know.

Tom, I had an Exterminator take a look at and smell the odor. They are convinced that it is not an odor of a rodent or dead animal. Everything looked good to them. They also can not define the odor.

I did take apart the hose from the dishwasher to the disposal and found some debris stuck in the hose and cleaned with a snake and bleach and multiple dishwasher cycles. I decided to cut the cabinet floor open, all clean, I then pulled out the 2 pvc kitchen drain pipes. I then pulled out the Disposal. I pulled out the instant hot dispenser. I pluged up the sewer drain holes and have the cabinet empty except for water hoses and diswasher hoses. I still have the odor but can't define it. Need some new ideas?

Some where in that cabinet the smells just got to be stronger. It's coming from somewhere in there. It sure would help if you could define the odor. Then we would know where to start. Let's think "outside the box" for a minute. We've been focusing on the obvious, sewer gas or a dead critter. Could you have spilled something in the cabinet that could have leached into the wood? With everything remover from the cabinet is the smell, stronger? Weaker? About the same?
Is there anything different on has anything been added lately? No matter how trivial? Ya got me stumped! Let me know if you come up with anything. Tom

Tom, thanks for your ideas. After removing everything possible the odor is about the same maybe a little weaker. I pulled out the dishwasher and checked no problems. I like your idea of the cabinets. We did keep a garbage pail under the sink and we had an Instant hot dispenser that would get hot against the cabinet. Maybe the odor is in the Cabinet. I got a Scunci Steamer as seen on TV, and I just steamed all the wood surfaces and under the floor area and all the remaining hoses and pipes, also the cabinets in and out. Lets see if the steam helps and I will give it a couple of applications over the next 2 days.

I've read your postings (tf123 and speedball) with great interest as I have the same problem. Plumber couldn't find anything. Had a critter guy come out and he 99.9% guaranteed it was my garbage disposal. In fact he was so sure he didn't charge me for the visit nor did he check for any dead critters. Garbage disposal was replaced last week and that wasn't it. The smell is still there. I just don't know what to do next. This has been a problem for over a month now. If it was something dead wouldn't it have decomposed by now?
Thanks.

Hey Blossom,

About the best you're going to do is follow the postings sent by users with the same problem. Sooner or later someone's going to come up with the answer.
We've explored all the possibilities and come up with zip. I have no more suggestions and can only hope that somewhere out there someone will stumble on a solution. So keep on checking this thread. I know I will. Cheers, Tom

Some sink strainers have a liner (usually to make the strainer match the color of the sink. Try removing the liner and seeing if there is any slug between the liner and the sink strainer. Cheers

I too, had the foul odor coming from under my kitchen sink. Unfortunately it was caused by a leaky old iron drain pipe under my home. I did as some of you suggested and replaced the entire iron pipe with PVC and the leak is fixed.

HOWEVER! Because it took me so long to discover just what the smell was and from where it was coming, I now have a standing puddle of sewer water under my floors. The puddle is maybe 4’x 6’ and at most an inch deep. Luckily it isn’t from a toilet drain, but the sewer smell is still pretty disgusting.

I have a crawl space (if you want to call it that) under my floors and so it is not practical to just sop up all the water or try to cover it with fresh dirt or other such material. I do have the vents opened under the house to allow for air to circulate, but because the temperature is now hovering around freezing, I’m not sure how much good it is doing. And I do not want to cause more trouble by freezing the surrounding water pipes.

Is there a product I can sprinkle on the puddle that will help “digest” the organic matter and thus clear the air even if the water is still there for the winter? I hate to use a bleach or similar product because of the strong smell it will leave behind. What I am in need of is a SUPER POWDER that will take all the smells away. I was thinking of maybe a septic tank cleaning additive or like product. Any suggestions?

Hi Bill,

Have you considered using quick lime? You may get some information from this. Good luck, tom


Clean It - Dry It - Disinfect It:
Mold and Mildew Control
By Jane K. Frobose, Colorado State University
Cooperative Extension, Denver County
October 1, 1999

Although the headlines have focused on North Carolina, damage from heavy rains and flooding can happen anywhere.

While Coloradans can feel somewhat immune from the havoc of a hurricane, no one is completely safe from the possibility of household plumbing accidents.

Just ask anyone who has encountered a plumbing problem. Water unleashed can cause huge damage to a home. A normally dry, semi-arid atmospheric environment can become a moist breeding ground for molds and mildew. Water damage also is a problem.

Molds produce mildew, a growing organism, gray to bluish-green. Molds grow in damp, warm, poorly aired and dimly lit areas. Eliminate growth factors and the problem can be kept to a minimum.

Generally, you can find mold anyplace where moisture or relative humidity levels are high -- wet or damp basements, for example. Here mold can grow on walls, floors or carpeting. Moisture from the earth can migrate through concrete walls and floors.

Water from utility backup, leaky pipes or condensation from an air conditioner or dehumidifier can support mold growth. Some building materials -- plaster, drywall, insulation, wood and wood flooring -- can wick moisture beyond the original wet spot.

Affected areas and items must be cared for immediately. Clean it. Dry it. Disinfect it.

Use a grease-cutting solution of detergent and water to wash walls and floors. Rinse with clear water to remove cleaner residue. Trisodium phosphate (TSP) effectively cleans grease, soil and flood residue. Take precautions when using harsh cleaners. Wear rubber gloves and avoid breathing the powder or getting it in the eyes.

Use large fans and dehumidifiers to dry a wet area quickly and thoroughly. Empty the dehumidifier's water collection pan frequently. Mold can grow in the standing collection water. If outdoor air is dry, leave windows open to promote drying.

It can take several weeks for wood and building materials to dry completely. Sun drying is effective for portable items, but do it carefully. Sunlight kills mold, but it also can fade textiles and other natural surfaces. Completely dry all items and areas before rebuilding, re-packing or storing.

It is nearly impossible to clean and dry carpet padding, upholstered furniture and soaked mattresses quickly enough to prevent mold growth.

Disinfectants kill mold growing on hard surfaces such as walls and hard floors. Disinfectants must be registered with the Environmental Protection Agency with an EPA registration number on the product label.

One of the most effective and least expensive disinfectants for hard surfaces is chlorine bleach. Use only bleach with 5.25 percent sodium hypochlorite. Follow directions on the label or use a solution of one-half to three-fourths cup bleach to one gallon of water. To kill mold, keep the solution on the affected area for 10 to 15 minutes. When cleaning with a chlorine bleach solution, wear rubber gloves and protect skin. Keep the solution away from eyes and skin and avoid prolonged breathing of vapors. NEVER mix bleach with ammonia or other household cleansers containing ammonia. Before disinfecting, clean hard surfaces thoroughly with a detergent solution.

If permitted to grow, molds and mildew can cause considerable damage to furniture. If left unattended, fibers and fabrics can be discolored and unrepairable fabric rot can result. Natural woods and fibers tend to be the most affected. Brush the mold off outdoors, so spores do not scatter within the house. When using a vacuum, dispose of the cleaner bag. It will contain mildew-producing fungi.

If safe for the fabric, launder washable items with detergent and chlorine bleach. Do not dry until all stain has been removed. Avoid piling wet clothes or other fabrics. Moist, warm and dark conditions in the pile's center provide excellent growing medium for mildew. Take nonwashables to the dry cleaners. Identify the stain for best dry cleaning results.

The following guidelines will help control mold and mildew growth in water-damaged homes:

Promptly clean and thoroughly dry wet carpeting, upholstery, clothing and household items.
If water is in your basement, quickly remove as many items as possible -- furniture, carpeting and stored boxes of household items. Remove standing water promptly and use a disinfectant or light chlorine bleach solution to scrub walls and floor.
Mildew grows best in a moist, dark, warm environment. Use fans to circulate air. Dehumidifiers will remove excess moisture in the air.
Spores from mold and mildew could be dangerous to your health. Take care when working with items that smell musty or are filled with mildew.
For a fact sheet about this topic, contact Jane Frobose, Colorado State University Cooperative Extension agent for Family and Consumer Sciences in Denver County, Colorado at (303) 640-5276 or e-mail at [email protected] or contact your local Colorado State University Cooperative Extension office.

Just checking in... I still have the smell under my kitchen sink. Three different plumbers couldn't find anything wrong. Another company confirmed it's not something dead under the house. Garbage disposal has been replaced. Instant Hot unit has been removed. I've scrubbed out the entire cabinet. All the supplies, etc I had under there have been removed. Right now I have three open boxes of baking soda under there and that has helped but not cured the problem.

I'll keep checking this thread. Thanks.

tf123 - did you ever solve your problem? Sounds exactly like mine.

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

I have just got done reading this thread, great answers by everyone.

I too have just recently developed an odor under my kitchen sink.

Just a week ago I replaced the kitchen sink and faucets. Not long after I replaced everything I started smelling an odor that I think is sewer gas. You can't smell it from the on top in the sink drains (double sink, disposer on left), but it hits you under the sink. I have my traps in both sinks, dishwasher drains to the disposer. I checked for leaks, and there is nothing.

My PVC pipe drains through the back of the cabinet.

Even though I didn't really disturb the main pipe when I changed everything out, I'm thinking that the vent pipe beyond the cabinet could have somehow been loosened, or maybe the drain pipe on the elbow maybe was loosened... just on the top.

My question is what does the vent pipe look like? I'm assuming it's just a PVC pipe coming out of the top of the drain pipe.

I haven't opened up the back of the cabinet yet, but I'm figuring it's my next move.

Any comments, let me know.

I too live in a new home (we renovated it completely) and there is a weird musty smell that I cannot identify coming from the sink area. I can smell it under the sink and near the light switches mostly. It is our bar sink though and is only used about twice a year so I can't imagine there would be a leak anywhere? There is no warping under the cabinet where the sink is. Please help!

I too live in a new home (we renovated it completely) and there is a weird musty smell that I cannot identify coming from the sink area. I can smell it under the sink and near the light switches mostly. It is our bar sink though and is only used about twice a year so I can't imagine there would be a leak anywhere? There is no warping under the cabinet where the sink is. Please help!

Bar sink has a P-trap. Trap has standing water in it to prevent sewer gas from entering living areas. That water will dry out and your sink drain will automatically become sewer vent. Solution: run water in the sink at least 1 x a week to keep P-traps wet.

Also, each drain should have vent. Vent should either terminate above the roof or close to the P-trap via AAV device. It may be that the plumber left vent pipe open inside the wall. I am assuming that based on your comment that you can smell sewer gas "...near the light switches...". Solution: cut open wall under the sink and inspect pipe going upward from San-T. See if you can determine whether this pipe continues upward in one piece or if it was left open. If you find out there is AAV device, you may replace it since it may be not working properly. I am enclosing sketch of typical drain/vent/p-trap detail to better illustrate the point...

Let us know what you have found out... Good Luck... Milo

Wow thanks for the quick response Milo! I can't wait until my husband gets home so we can look into it. One more thing, there is a large window right above the sink (it goes about a foot wider than each side of the sink) so could there still be a vent here? Maybe that is the problem. I took pictures of all the walls before they closed them up (although the insulation covers a lot of it). I attached the photo although you can't see much but maybe you might see something I don't in it! I labeled it for perspective!

http://i195.photobucket.com/albums/z315/ahackshaw/Drainwall.jpg


Bar sink has a P-trap. Trap has standing water in it to prevent sewer gas from entering living areas. That water will dry out and your sink drain will automatically become sewer vent. Solution: run water in the sink at least 1 x a week to keep P-traps wet.

Also, each drain should have vent. Vent should either terminate above the roof or close to the P-trap via AAV device. It may be that the plumber left vent pipe open inside the wall. I am assuming that based on your comment that you can smell sewer gas "...near the light switches...". Solution: cut open wall under the sink and inspect pipe going upward from San-T. See if you can determine whether this pipe continues upward in one piece or if it was left open. If you find out there is AAV device, you may replace it since it may be not working properly. I am enclosing sketch of typical drain/vent/p-trap detail to better illustrate the point.....

Let us know what you have found out....Good Luck....Milo

Hackshawash: Yes, indeed, many times sink is centered on kitchen window. In this case we install so called "dirt arm". Basically, what it is an unvented horizontal drain pipe that connects to San T , located on side of the window and past by structural Trimmer and King Stud ( window framing ). Therefore it connects to Drain/Vent pipe. This horizontal pipe should not be longer than 5' for 2" pipe and 4' for 1 1/2" pipe with slope of 1/4" per foot. See the drawing to illustrate the point...

Thanks you for posting the photo. I cannot see whether it is installed correctly because there is insulation in walls. Peal it off off and see what's there... Maybe you could take another photo and post it for us to see. Thank you. Milo

That photo was from a year ago. There is drywall and cabinets in front of it now. Now I wish I'd taken photos before the insulation was in! One more question. Does the pipe going up to the vent have to be in line (i.e. directly on top of) with the pipe going to the sewer or can it be offset? Thanks for the help!

If it is not decaying food or a deceased animal that is causing the smell, it is most likely an odor from a mold problem that could be growing in the cabinetry wood or walls around the sink. This is often a problem where there is a pipe leak (whether large or insignificant) or simply where humidity is high. I would look closely to see if there is mold growth around that area. When you smell it, that means that is has reached the surface somewhere, dried up, and became airborne so that you breathe it in.

Well after 18 months,a plumber and replacing a garburator and all the pvc under the sink twice the smell under my sink is gone thanks to the persons that mentioned the black rubber connector from dishwasher tube.Must have been off gasing or something. Actually when I first moved in I thought it was the carpet underlay that was stinking up the house so I replaced all the old carpet and underlay. Same kind of smell. Thanks again folks!

Another possibility I have come across a few times is that threads have rotted out on galvanized pipe being used as the vent. You could drop some peppermint extract down the roof stack or do a smoke test to find out.


Sorry if I restated anything. I didn't realize there were seven pages of responses until just now

Time to put this six year old thread to rest guys. Tom

Well... hopefully Rusty (of the original post) has moved on since '04, but I'll add my findings in order to maybe helped the next person with a stink under their sink.

For me, it seems that problem stems from a small obscure leak from the [lifetime] faucet that we wetting the inside back panel of the sink base (cabinet). As is mentioned else in this thread, there ~should~ be a distinguishable difference between the smells of a dead critter, sewer gases, mold/mildew, and... wet luan/plywood or compressed wood. However, when you're having trouble identifying the source, you start to second guess your nose.

Having found the leak and the warped luan, I can 100% WITHOUT A DOUBT believe that I found my problem... unless it doesn't go away then I'll start to re-think the dead critter possibility.

Just wanted to say I had a strong musty smell coming from under my sink as well and I think I figured out the problem. I took apart the pipes from under the sink and found that a muddy substance was sitting on the trap ( I guess that is what it is) A while back I repotted a plant and I washed some potting soil down the drain and it turns out the soil stayed stuck in the trap. :( Lesson learned don't wash dirt or potting soil down the drains.

O.K. I also had this smell under kitchen sink. No leaks, removed a few dead rats from crawl space, used "drain care" through drains and dishwasher, used clorox, ran hose down vent pipe... the answer... that same smelly black hose that runs from the air gap to the disposal. Ours had a sag in it that may have allowed food to rot in there... funny, it didn't seem to smell that bad... maybe it gradually gives off the smell and when you open the cabinet, boom! Anyway, replacing this hose solved our problem (disposal was replaced too--it was really loud) but I think it was the hose.

Roshoi, roseande and jimheyek,
Same complaint different solutions.
We thank you for your input. '
Your solutions should help many people with the same problem.
Thanks again, Tom