Musty smell from one of my double sink drains.
#1
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All of a sudden we've got this moldy musty smell coming from the left side drain of our kitchen double sink. Its the side that has the 90 degree pipe. I've tried: Baking soda + vinegar, boiling water, bleach, cleaning the drain as best I could with a long narrow plumber brush and liquid enzyme "super odor eliminator" = FAIL.
I've repeated some of these and left the drain stopper on and have determined the right hand side is fine.
There's no garburator and the drains flow freely. Its not a sewage smell at all, just musty. Its bad enough that if we leave the drain open for a time it stinks up the whole kitchen.
My next step (short of an exorcism) would be to remove the 90 degree pipe and sanitize it but each joint looks to be glued (looks greenish yellow). What the what can I do?
I've repeated some of these and left the drain stopper on and have determined the right hand side is fine.
There's no garburator and the drains flow freely. Its not a sewage smell at all, just musty. Its bad enough that if we leave the drain open for a time it stinks up the whole kitchen.
My next step (short of an exorcism) would be to remove the 90 degree pipe and sanitize it but each joint looks to be glued (looks greenish yellow). What the what can I do?
#2
Replacing the arm that goes to the left will be doable and we can guide you through that.
Before doing that though, I wonder about the smell.
- Does the counter have a wood underlayment and do you think water has intruded through the sink perimeter into the wood, meaning a bad or failed caulk joint and mold?
I see no reason this drain would smell, especially after cleaning. By U.S. standards, your AAV vent is too high above the trap arm. That could allow sewer gas to come up, and the gas is favoring or drifting towards the left side.
That's a guess. Everything under your sink looks fine except for the AAV height.
Before doing that though, I wonder about the smell.
- Does the counter have a wood underlayment and do you think water has intruded through the sink perimeter into the wood, meaning a bad or failed caulk joint and mold?
I see no reason this drain would smell, especially after cleaning. By U.S. standards, your AAV vent is too high above the trap arm. That could allow sewer gas to come up, and the gas is favoring or drifting towards the left side.
That's a guess. Everything under your sink looks fine except for the AAV height.
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Thanks Brian- The under-counter is dry and there's zero smell under the sink. We have a septic system and I don't suspect its the issue. The smell is really like moldy soil, almost peppery ?! Also, of all the cures I tried, the addition of anything hot seems to have a rebound effect again pointing me to some .... growth.
When we bought the house last summer there was a bit of a smell but the house had been vacant & sweltering for a few days. Once we started using the sink it went away. A few weeks ago family members brought a roast, did dishes (lucky us!) and I suspect they inadvertently poured a fair bit of fat down the drain. It seems to have kicked this off but it did not clog the drain at all.
We happen to have a plumber's wrench; can I unscrew the PVC pipe or is that permanently glued on you think? I read that some PVC glue is as good as soldered.
When we bought the house last summer there was a bit of a smell but the house had been vacant & sweltering for a few days. Once we started using the sink it went away. A few weeks ago family members brought a roast, did dishes (lucky us!) and I suspect they inadvertently poured a fair bit of fat down the drain. It seems to have kicked this off but it did not clog the drain at all.
We happen to have a plumber's wrench; can I unscrew the PVC pipe or is that permanently glued on you think? I read that some PVC glue is as good as soldered.
Last edited by FLMcDougal; 04-15-16 at 06:21 AM. Reason: forgotten answer
#4
The pipe is ABS and it's glued. The only parts you can unscrew are the tailpiece nuts under the sink strainer baskets and the large trap nut.
I need to go to work for awhile, I or someone will get back on the best way to swap out the pipe with new.
Removing all three nuts mentioned above will allow you to drop the entire assembly down if you want to inspect it or clean it. Place a pan under trap before loosening, the trap will be full of water.
I need to go to work for awhile, I or someone will get back on the best way to swap out the pipe with new.
Removing all three nuts mentioned above will allow you to drop the entire assembly down if you want to inspect it or clean it. Place a pan under trap before loosening, the trap will be full of water.
#5
Remove what can be removed, it's not hard at all, and clean. You WILL find a lot of crap inside the horizontal pipe.
Elbow p-trap will also be filled with junk. So you need to remove everything from the main vertical drain back to sinks.
Take pics before disassembly and mark parts with silver marker, so that you can put everything back together. It's stinky job but gives excellent results.
Elbow p-trap will also be filled with junk. So you need to remove everything from the main vertical drain back to sinks.
Take pics before disassembly and mark parts with silver marker, so that you can put everything back together. It's stinky job but gives excellent results.
#6
I noticed your dishwasher drain isn't connected properly. The methods of connecting the drain comes up very often.
This is now my suspected reason for the smell, especially if you don't use the dishwasher regularly.
Water that has been trapped in a hose is very stinky.
I'm surprised there's not water pooling in the bottom of your dishwasher, and that stinks also.
Where your dishwasher attaches to the drain is either below flood level of the trap or just barely above it.
Post back for instructions on proper install of the drain hose.
This is now my suspected reason for the smell, especially if you don't use the dishwasher regularly.
Water that has been trapped in a hose is very stinky.
I'm surprised there's not water pooling in the bottom of your dishwasher, and that stinks also.
Where your dishwasher attaches to the drain is either below flood level of the trap or just barely above it.
Post back for instructions on proper install of the drain hose.
#7
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Thanks again Brian. Attached clearer picture of drain hose install. From comparable installation pictures it seems the loop isn't high enough? I see some debris in there as well.
But I have A) No dishwasher odor or issue B) the right side drain, the one closest to that dishwasher drain hose doesn't really smell whereas the left side is pretty strong (we've outright condemned it and keep it shut in the meantime).
But I have A) No dishwasher odor or issue B) the right side drain, the one closest to that dishwasher drain hose doesn't really smell whereas the left side is pretty strong (we've outright condemned it and keep it shut in the meantime).
#8
Looks to me like you have 3 connections that can be unscrewed... one at each sink tailpiece and one at the trap. Why not unscrew those connections, drop it all straight down as a unit and clean out the pipes with a pipe cleaner?
#9
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It's hard to tell, but is the horizontal pipe actually pitched at all? I wonder if there's water and gunk in there.
#10
Yes... it looks pitched the wrong direction and is probably holding water.
The dishwasher drain needs to exit the dishwasher and make a loop all the way up to the bottom of the countertop and then down to the drain.
The dishwasher drain needs to exit the dishwasher and make a loop all the way up to the bottom of the countertop and then down to the drain.

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The section in the middle is not pitched at all. Tomorrow I plan on unscrewing the junctions - which look unglued - removing that whole section and totally sanitizing whatever I can get my hands on. If that doesn't work I'm calling a priest ;-)
Will report back.
Will report back.
#12
Looks like you can put 1/2" of pitch on it by pushing the joint as high as it will go on the left tailpiece.