Foul smelling cold water from faucet


Old 04-16-04, 05:16 PM
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Foul smelling cold water from faucet

Have a question:

I live in San Diego, in a condo built in 1991. For the last year, I've noticed that one of my two bathroom sinks (next to each other in a side-to-side setup) has a quirk, where when I just initially run cold water, there's no smell for a second or so, and then for the first 10-15 seconds there's a distinct sewer smell to the water. It subsequently goes away as I run the water, and does not return when the water is on.

It only seems to occur if 1) I haven't used that cold water faucet in a number of hours, and 2) only in the afternoon and evening. In other words, if I use it again after a few minutes, then there's no initial smell, and it's never been a problem when I first wake up in the morning. No other faucet in the house does this, and aside from some mild water hammer in the toilet (coinicidentally next to this sink), there are no obvious plumbing issues in the house.

Any thoughts?
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Old 04-16-04, 06:39 PM
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Have the pressure tested to see if high pressure is causing the fill valve to cause water hammer.

Now, this might be suspicious, and worthy of comment, but I have seen situations where the fill valve in toilet was defective, and allowed for water to pull from toilet tank into other parts of the system.

One noted case involved a situation where the customer complained of having "blue water". Turned out the reversal of flow was pulling water from the tank into the potable water system and discoloring the water to a light blue. There was a blue disk setting inside the tank for cleaning, which was partially responsible for the fill valve failure.

Even though those ballc.ocks are anti-siphon, they can, and will fail.

Is this what is going on in your case? I doubt it, but cannot rule it out. The probability is almost unlikely.

You might want to try replacing the aerator on your faucet; these can become contaminated and a breeding ground for bacteria.

It might have specs of rust in the flow restrictor that is deteriorating causing the smell or other type of debris that is possibly souring while not in use for some time.

It is all a guesstimate, but I would replace the $3 aerator and see if this solves the problem first, then post back with your results.
Old 04-17-04, 11:30 AM
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Thank you for your reply. I checked the aerator, and it looks quite clean, no rusting or other bits. My next step will be to check the toilet fill valve - can you give me a brief set of instructions on how to proceed?
Old 04-17-04, 12:13 PM
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Have you tried the idea of removing the aerator for a few hours to determine if the aerator is the cause, and is the inside of the toilet tank dirty?

Replacing a fill valve is simple for a toilet. I just can't say for sure the fill valve is the problem, so I am hesitant to advise replacement of the valve.

Something in your potable water system is the culprit, but not being there to see all situations present makes it impossible to rule out other things that might be the cause.

Any chance there is a house filter that hasn't been changed, a set of faucet supply lines that might be holding the odor, so on.
Old 04-17-04, 01:56 PM
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I suspect that it may not be the water at all but the overflow on the sink or drain itself. These can get gunked up over time and cause a sewer type smell. I would suggest first cleaning the traps on both sinks. If that doesn't work plug the overflow exit on the lower drain and fill the sink overflow with a bleach solution.
Old 04-18-04, 07:16 AM
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Hello: helper94

Most likely the overflow in that specific sink is the direct cause of the condition. And the likely solution is to first follow the suggestion offered by Rainbird.

If the stopper cannot be removed from the sink, instead of unconnecting it, below in the cabinet on the piping, simply flood the overflow with bleach.

Not as good as plugging up the over flow but will help. The excess blrach will flow into the elbow (trap) and kill germs in there also. Hence, two places (overflow & trap) in one application.

Other possible conditions, like those suggested by Dunbar, are also possible. Try the overflow solution as a first step attempt.

Regards & Good Luck
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Old 04-19-04, 01:07 PM
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If that doesn't help... An odor of H2S that is only in one area of the building is usually caused by bacteria. Especially a hot water only odor. The faucet tip may be contaminated and the bacteria have migrated into the plumbing. There could be a trace of H2S in the water coming from the well that unless you spray the water into a bucket while hanging your nose on the rim and smelling for it, you may not know of it.

Natural or bacteria caused H2S will usually show up at the highest and most infrequently used fixtures.

Gary Slusser

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