How to fix weird sink smell
December 16, 2009 9:10 PM   Subscribe

Lately the cold water in my bathroom sink has a musty odor when I first turn on the tap. What should I do to fix this?

Last year we installed a new sink and it worked great for many months afterwards. For the last few months, I've noticed that the cold water smells moldy (kind of like lake water) when I first turn it on. The smell disappears after I've run it for about 20 seconds.

Strangely, the hot water from the same sink does not have this smell, nor does either the cold or hot water in the shower in the same bathroom have it. In fact, no other sinks in the house seem to have this problem.

I saw this similar post but it's for a kitchen sink/garbage disposal, so the advice doesn't seem to apply. Is there anything I can do, aside from calling a plumber, to fix this problem?
posted by tomwheeler to Home & Garden (7 answers total)
Well, that smell sounds like stagnant water. Could be an issue with the pipes -- is something "behind the scenes" cockeyed and letting water sit?
posted by desuetude at 9:16 PM on December 16, 2009

Take off the aerator on that sink, and clean it out really well. That could help, as little bits of stuff gets caught in the screen.

Agree that something in the pipes could be causing the odor. It could even be solder from the installation!
posted by Jinx of the 2nd Law at 9:57 PM on December 16, 2009

Had this problem last week, and wound up throwing away the cold water filter by mistake. But the problem was indeed a gunked-up aerator. It didn't respond much to scrubbing or soaking, but the $3 replacement from the hardware store resolved the thing.
posted by nakedcodemonkey at 10:07 PM on December 16, 2009

I also had an "EW what is in the AERATOR" problem this month, so I'd suggest starting there.
posted by fairytale of los angeles at 10:21 PM on December 16, 2009

If the aerator doesn't solve your problem, check your plumbing for any 'dead legs.' These are lengths of pipes over 3 inches that have no outlet, or lead to an unused faucet. These may be old pipes leading to a sink that someone removed during a remodel or something like that. All sorts of organisms and biofilms can grow in these stagnant pipes that can lead to water that smells like a lake and even worse things like legionella (googling gives a good overview here.) Obviously, longer dead legs lead to greater volume of stagnant water which can affect the rest of the system.
posted by kuujjuarapik at 8:16 AM on December 17, 2009

Start with the aerator, then also if you have one of those flexible water lines between the faucet and the wall, check that too. Sometimes they can get moldy and gross. Also a cheap thing to replace.
posted by spilon at 8:33 AM on December 17, 2009

As a follow up, I didn't think the aerator would be the problem since the smell is only on the cold water and the aerator is used for both hot and cold water. I tried cleaning it anyway since it was an easy fix, but alas, it didn't fix the smell.

I had a plumber come out and look at it and he thought the flexible supply line was the most likely cause. Since the fittings are specific to the sink model, I had to order replacements from the manufacturer. It seems to have been the solution, so I am marking spilon's as the best answer.
posted by tomwheeler at 12:08 PM on January 17, 2010

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