It's strange because before we remodeled our bathroom we had a Kohler porcelain sink and never had an odor problem. If it is a vent problem why does Liquid Plumber fis it?

Did you change the vanity and p-trap when you remodeled? Can you post a picture of the plumbing under the sink?

We didn't replace the vanity. I had our plumber do all the plumbing. I think he put in new plastic p-trap and connections that were needed. Sorry, I can't post a picture. When I noticed the odor, I had him come back and check. He couldn't find anything wrong, but just in case I was smelling the plastic from the faucet attachment tubes he replaced those. That had no effect.

Your plumber may not have done the installation correctly. Sewer gas is really dangerous. Have another plumber come in and evaluate the situation for you.

Let me add to the chorus, it is not the sink, it is the plumbing. There is supposed to be water in the bottom of the p trap that is what blocks the smell. So when you dump a sink full of water down there, water goes where it should. If the slope is incorrect then the water is not staying in the p trap and when it slowly dries out you smell the gases. If you hate the sink, fine, admit it, but get the plumbing fixed. Don't blame the plumbing problem on the sink. If you change the sink, the next plumber will likely fix the plumbing (you will hire a different plumber this time correct?) and leave you in happy ignorance that the plumbing was the problem all along and you did not NEED to mess with the sink and the countertop.

I am still confused about why liquid Draino gets rid of the odor for several months. If it were just an empty p-trap the odor would return as soon as it drains. That does NOT happen. I believe the sink itself traps junk that begins to stink like sewer gas eventually. It could be the stopper mechanism also. The only way the trap could be involved is if the junk is hanging into it.

You've had a lot of people give you really good advice about fixing your plumbing. However, you sound quite resistant to this fix and keep coming back to your conviction that it's the sink. If you don't want to accept the advice, I think you should install a new sink. Either you'll solve the problem and be vindicated, or you'll accept that the plumbing is the source of the problem and get that fixed.

If it were just an empty p-trap the odor would return as soon as it drains. That does NOT happen.

How would you know? You've never checked the trap.

Having 2 females in the home, both with extremely long hair, I've never had a trap smell like sewer gas when the trap is becoming clogged. I will say the trap that I have a problem with is in the bathtub/shower. Both of them know better than to intentionally put hair down a sink drain.

If you need help with how to keep hair out of a sink drain, I'm sure anyone here is willing to give simple advice.

nerdyshopper:

You're mistaking correlation for causation. In Michigan in the summertime, a rise in ice cream sales and an increase in drownings are positively correlated. Obviously eating ice cream does not cause drowning.

Ok when you are cleaning the other pipes you can clean the overflow too. I am not aware of anything about the Corian sink that makes its overflow more likely to get yucky than any other brand… All sink overflows can get yucky especially in the bathroom where they are exposed to hair that holds, soap and toothpaste...

I need to post to this thread again because I hired a plumber to inspect my sink plumbing. He replaced the trap; cleaned the stopper mechanism and snaked up the stack and down to the main sewer. About a week after he left the odor returned. It will not go away when the trap is filled with water, but it seems to be worse immedialtly after I turn on the water. Seems to be there with both hot and cold water. I am going to purchase some more Drano Max gel and repeat what I did before. If that works it proves that my original postings were correct and that the odor is somehow related to the Corian sink.

nerdyshopper:

Corian and other solid surfaces are inert. They have no smell except when they are machined. Your Drano Max gel experiment proves nothing.

Get a new sink. Then see.

I wonder if your vent is not working.

Try posting on the plumbing forum.

PS - if you don't believe me, put your nose close to the drain overflow drain hole; if you run water when doing this the smell is a little worse as a small amount of air pushes up the overflow tube. If you still don't believe this, dis-assemble the overflow tube (you'll need to break the caulking bond from the tube to the sink and disconnect the plastic Corian fixture from the sink drain assembly); I guarantee you'll not like what you smell from the Corian overflow tube!! Corian really needs to address this with a bacteriostatic rubber line or something like that.

When I started this thread, I posted that I cured the odor problem by pouring liquid Draino down the overflow using a funnel and also down the drain. No one at this forum would believe me. I am glad that another Corian user had the same experience. I have the problem again and have some more Draino out in the garage. Today, I will clean it up again. This is a flaw of Corian sinks. I followed tha advice I got here and hired a plumber to take the trap apart and clean out the line and the air vent. It cost a lot of money and did nothing for the problem.

Corian sinks are designed no differently than any other sinks with overflows and do not need any more or less cleaning than any others.

Joe - I beg to differ. My sink stinks as does "Nerdy Shopper." Their overflow design is flawed and the plumber who finally got me a solution told me he has treated many in the past (not so much now as Corian isn't as popular according to him). Not going to start a text war here so we can agree to disagree.

My bathroom sink overflow sometimes smells bad and it is an 80 year old porcelain sink. It may not be the fault of the Corian.

Nerdy Shopper - I believe you as I have experienced the exact same problem. When the overflow assembly that was installed when the sink was new came out and I smelled the overflow tubing I about passed out. He installed one of the new ones from Corian after that and instructed me on how to maintain it. My wife and I really regret choosing Corian for the bathroom counter replacement. The Corian in our kitchen (sinks) don't have the overflow tubing and are fine One has a disposal unit and the other a regular kitchen drain.

Yes. Before I had a Corian counter-top with sink installed, I had a Kohler sink installed in the counter. In over 10 years I never had an odor problem.

I have the same problem from time to time with my 30 year old cultured marble sink in the bathroom. In my case, pulling out the stopper and giving it a good scrub with bleach and rinsing out the overflow generally will cure the problem for quite a while. Also, my shower drain will get stinky occasionally and again, removing the grate and giving it a good scrubbing with a bleach solution eliminates the odor. I live in a very warm climate and always wondered if the warm conditions contribute the microbe growth.

I had a similar problem. After twice snaking the drain and using draino the problem came back a month or few later. The third time I took apart the drain assembly to find a white film that stunk (mostly like a hair salon) coating the black part of the drain line. I also removed a lot of gunk from the over flow line. It seemed that hair would get stuck where the over flow meets up with the drain. I suggest a good physical clean out of the over flow line and drain followed by a good soak of each with something that kills germs and bacteria. To soak the overflow plug where the overflow meets up with the drain with a bucket underneath. It would be worth checking the level of the sink and drain lines.

I get a funnel that fits the overflow drain hole and pour liquid Draino ( the thick kind) into the funnel. I use about 6 oz. I let it stand for about 20-30 minutes, then I pour water into the funnel for about 4 rinses. That seems to dissolve the gunk. It takes about 2-3 months to build up. I think it is a defect in the design and there is no permanent fix.

+1 for this being a Corian problem. We get a sewerage smell from our basin, especially in the mornings, I guess because it's been accumulating unpleasant smells overnight. Not a great way to start your morning!

We had our plumber check it. He was adamant the plumbing was OK, but replaced the trap anyway, which didn't help. He suggested it might be the overflow tube and suggested cleaning with disinfectant. I was a bit doubtful as we've never had an overflow situation, but did it anyway. This helped for a while - the smell went away, or the disinfectant smell masked it, or maybe a bit of both. But it came back.

We went for Corian because we wanted a custom size basin for a small space, but really regretting it now. I'm thinking about looking at a custom overflow tube to solve it, but not sure what materials to use. In the meantime I guess we'll just need to keep cleaning. Would be good if Corian stepped up to solve the problem - it's a horrible recommendation for their product. Has anyone tried contacting them?

Until I actually see an explanation of how this is actually being caused, I remain skeptical that the only reason for this is that the sink is made of Corian. I'm not doubting that people are detecting odors, but I've had odors from my standard cast iron and enamel sink and I didn't attribute it to the material the sink was made of. If a large proportion of Corian sink owners were complaining about this, I'd be more open to the proposition that it's due to the nature of the materials. Just my 2 cents...

I don't think it's because the sink is made of Corian. I think it may be because of Corian's overflow drain design.

I had an integrated Corian sink in my bathroom until I replaced it and the counter top a few years ago. I never had this problem.

That said, I can't say that my Corian sink's overflow design was the same as my porcelain sink (before or after the Corian sink). The porcelain sink has an overflow molded into the porcelain - that is, the overflow tube is made of porcelain. In my Corian sink, the overflow was not made of Corian. It was a plastic tube that connected the overflow hole in the sink to a hole in the trap connection at the bottom of the sink. Perhaps the plastic tube can harbor more bacteria than either porcelain or Corian?

Corian is specified by architects for surgical wall cladding in hospitals. Natural stone is not. That should tell you all you need to know about Corian's sanitation. It cannot stink.

It's possible that some models have an overflow that is designed in such a way that it gums up more often than others. The Corian material is incidental. It's the goop growing inside it and that'll stink no matter what container you have it in.

I had the pleasure of fixing the overflow on a 65 year old sink which for some reason a previous owner had sealed shut at the bottom. So yeah, I know these things can stink if they aren't draining properly. Pink cast iron American Standard sinks can stink too!

fied:

Your points are well taken, but the bottom line is that Corian itself cannot stink.

There seems to be some confusion in this thread between Corian material and Corian sinks. I don't think anyone is disputing that the Corian material is quite inert and doesn't stink. The sinks, however, are a different story. They aren't built like most sinks with a double-wall construction, they have a separate tube. Here's a link to the one I have:

http://www.nantucketvanitytops.com/nantucket_sinks.html

You can see in the diagram how a tube runs from the front of the basin down to the drain. This tube seems to be the source of the problem, although I suspect in my case it's the fitting under the drain where the tube connects, as I had a smell problem despite never having an overflow occur.

And yes, I had a plumber check it and replace the trap. No other drain problems in the house including the other bathroom's sink. See Mike's comment a ways back - it seems like a design fault, and unfortunately frequent cleaning the only solution short of replacement.

I loved my corian bathroom. The shower the counters everything was Corian and I never had a problem. I did have that smell in the shower of my older home and there were numerous causes. The vent in the roof was blocked. The pipe going from the toilet to the shower was the wrong pitch so something was going on in the trap. Something about the overflow as mentioned above. All I know is that it took a dozen plumbers until one finally fixed it and the smell is gone.

Eleanor, was your sink the type with the drain hole at the front of the basin and a tube running to the drain?

Thanks, Dennis

There are stainless steel sinks with the overflow tube, same design as the Corian sinks. Neither stink.

Do you have a Corian sink Joseph?

Yes, with a plastic overflow. 3 years of regular use and no smell ever.

Thanks, not a consistent problem then. I guess not all Corian sinks stink, just some of them!

Easy solution. 95% of the time, this is all you need: https://www.homedepot.com/p/Zip-It-Bath-and-Sink-Hair-Snare-BC00400/100665735

This is a great idea Milly Rey. Yuck when I think of what my teenage daugher plugs the sink and shower with. You would not believe what I have found in the toilet! The only satisfaction is that one day she will have her own home and realize what a mess it is.

Dennis,

I have no idea really. I do know that after many plumbers it turned out to be the trap and the vent that were the problem and everything was tile. I would hear gurgling because I guess there was air in the void and the smell would come up. I even cleaned out the drain myself and found a mummified creature of some sort. The smell came from the vent and trap. I LOVE CORIAN and every contractor stears me away from putting it in my remodel. I think it is because the company installs it themselves and contractors really don't make any money on it. It was seamless, really easy to clean. Now I am told it is "outdated" and "everyone'' is doing Quartz or I "have to use granite." I really don't care what everyone is doing my bathroom counters and shower were never cleaner. It's funny that when I look on line at things I cannot afford and are really unique everything seems to be from Italy and I cannot tell you how many times the tubs, walls and counters are made of Dupont Corian. Here everyone poo poos it.

My bathroom sink is porcelain and I sometimes get a whiff of sewer gas when I am brushing my teeth. Usually the water was just turned on for a second and then turned off. I am the only one who has ever noticed it as far as I know.

We are about to do a complete remodel of this bathroom. Should I get the vent stack inspected? What other things can I do while it is pulled apart to ensure there is no problem? There have been no problems with the tub drain or the toilet flushing. I would hate for the new sink to have the same problem.

You should never smell sewer gas from any sink; that's what traps are for. Have your vents and drains tested, please.

The OP has a valid concern. I too have a Corian sink and have noticed it smells more than my previous porcelain sink. The Corian material is not the problem, the problem is that Corian has a terrible overflow drain design. It’s a plastic box that’s glued onto a vent cutout of the bowl. The box is glued with silicone and a soft flexible plastic tube connects the overflow drain box to a custom ring fitting at the bottom drain in between the bowl and the P trap. This fitting and the plastic tube appear to be made of a material that supports bacteria that thrive on essentially soap, sweet toothpaste, and saliva. It’s nasty smelling. Cleaning it with bleach once a week is needed to keep it at bay. The plastic tube and fitting apparently are just the opposite of being anti-microbial. A tube and plastic fittings infused with silver powder would probably fix it permanently.

The oither problem that after time, the plastic box that covers the overflow drain eventually comes off because the glue or silicone fails or debonds, it is a major hassle and a poor design. I wish I had porcelain sinks with integrated overflows.

Those who who keep insisting the problem is the plumbing must have never seen what the overflow tube looks like. It’s this soft pliable white rubber material.

I have a double vanity and they both have this issue, with the tube coming off and the pipes are full of nasty bio stuff that just clogs the sink no matter how much you clean it.

I know this is a old (and long) thread but I figured I would put in my 2 cents. I have two Corian bathroom sinks that are around 15 years old. I have the same issue with smell.

I believe the problem is with the way the overflow tube (see James L photo above) connects to the drain under the sink. It is so tight to the sink that it ends up being horizontal by the time it connects to the drain.

I think the water going down the drain backs up into the tube and doesn't drain out. So, whatever is in there with the water sits in the tube and grows funk. The only way to get rid of the funk is to pour something like bleach in the overflow.

While this is technically a plumbing problem, it is really caused by the design of the sink. This is an old design so maybe they have a better overflow design. One possible solution I may try is to use PVC instead of the tube and connect it further down the drain tube but still above the trap.

This will require capping off the old spot where it connected and figuring out a way to connect the PVC to the overflow. I suppose you could use some other type of tubing that works better. The main thing is to have a constant decline all the way to where it connects to the drain.

I came up with a workaround that should eliminate or significantly reduce the stink. Besides the overflow tube being a horrible design, the round piece that connects to the bottom of the sink (2nd photo) seems like it is designed to grow nasty stuff.

By the way, I originally tried replacing the white tube with the clear tube in the photo. I did this without any modifications. The water backed up so bad into the tube that there was at least a half inch by 4 inches of water sitting in the tube at all times. The old tube actually had mold growing all the way up to the top of it. And, I flush it out with bleach often.

I took the drain apart and removed the round drain piece connected to the bottom of the sink. I replaced the overflow drain with a non-overflow drain with a pop-up stopper. The overflow tube was diverted further down the drain pipe so that there is more of an angle. The water no longer backs up into the tube. It required a little creative engineering to connect the tube to the drain.

The plastic piece that connects to the overflow hole at the top of the sink also came off (as other people have mentioned) when I put this all together. I cleaned it and the sink up good. For the plastic piece, I used a carpet blade and a flathead screwdriver. Then I used a Dremel with a pointed grinding type bit to etch both the plastic and the Corian to make sure the adhesive would stick. I used Loctite PL Marine adhesive sealant and it worked great. This stuff is super sticky so make sure you wear gloves. Also, let it dry for at least 24 hours before assembling everything. If you can, use some sort of shims to wedge between the plastic piece and the cabinet. If you don't have shims, just hold it in place for a couple of minutes.

Hopefully this works to get rid of the stink. At least it will be a lot easier to clean out with bleach every now and then. I did this modification for both my Corian bathroom sinks and it is amazing how good the bathrooms now smell (or don't smell).

That's great jaybfl, thanks for sharing. I'm not as handy as you and have doubts I should be performing surgery on my vanity, but I'll give it some thought. Be nice if Corian took some responsibility for their bad design and provided a kit, but so far as I know they are still selling this type.

So glad that I found this post. Had a corian countertop with corian sinks installed almost 18 years ago. It is in the bathroom my daughters use. They were constantly complaining that their water smelled like rotten eggs. I couldn't understand why their water smelled and mine didn't. I found this post because like other posters, my overflow drain "ramp" is no longer connected to the sink. One disconnected years ago and now I have noticed that the other one no longer connected. It is difficult to find a corian installer in my area. Anyway, it is nice to know why their "water" smells (actually the drain and not the water.) . I believe that Mike and the original poster are correct as I have experienced the same problem. I agree that it is a poor design for the overflow drain.

So glad I found this thread. We have 6 Corian sinks throughout the house (about 20 years old). Never any issues with smell. After replacing two bathroom faucets (in the middle of replacing all of the faucets), an awful smell started emanating from the drains of those two sinks I replaced the faucets on. I think this is why:

When I was replacing the drain stopper (installed a pop-up drain), I took off the overflow valve (this was necessary to replace the old lever-type drain stopper). When I removed the overflow valve, the part that connects to the drain of the sink is like a donut with a hollow inside that had equally sized compartments. Looking inside that “donut”, it was totally stuffed with what looked like little pebbles. I thought this was gross gunk that accumulated over all the years and washed it out. I think those pebbles were actually to protect that drain from accumulating gross gunk.

so, when I rinsed out the “donut” drain, it became totally hollow inside, ready to accumulate gross stuff going down the drain. The smell is strongest after you turn on the water. it’s not the P trap.?the previous P trap was metal, I had to replace it with another one that is plastic. there’s definitely water in the P traps.

so again, never any smells, then bad smell as soon as faucets were replaced and “gunk“ that filled the donut drain and prevented real gunk accumulation was removed, causing that drain to began to accumulate gunk and smell.