I keep two glass bottles filled with tap water in a small fridge in my bedroom. The tap water smells fine out of the spout. A few days ago I noticed that the tap water begins to smell bad after sitting in the bottles for a few hours (in the fridge or at room temperature, it doesn't seem to matter). This is a brand new behavior.

As an experiment I boiled some tap water and put that into the (clean) bottles for a few hours. Previously-boiled tap water begins to smell bad after a few hours too.

I have a well and everything's been swell for the past four years. I have a water softener which seems to be working fine. My pressure tank is fairly recent (a few years old). It has been (quite) a while since I've had the well checked or the water tested.

Any ideas?

  • 3
    Have you tried different bottles just to rule that out? Can you recognize any of the smells? Sulfur, chlorine (unlikely if you are on a well), etc.
    – Steven
    Commented Mar 26, 2012 at 19:54
  • Yes, I am experimenting with a different bottle now. Thanks.
    – Alan
    Commented Mar 26, 2012 at 21:23
  • @Steven - It seems that it was indeed the bottles. I'm going to test the water anyway, just to be sure.
    – Alan
    Commented Mar 28, 2012 at 19:49
  • @Tester101 - Thanks for rewriting my non-question title into a question title. That makes the Internet better. But why remove the "thanks" at the end of it? There's nothing wrong with polite appreciation.
    – Alan
    Commented Mar 28, 2012 at 19:50
  • @Alan Valedictions and signatures make the questions feel more like letters. Since we're asking questions; not writing letters, valedictions and signatures are just noise. You don't have to thank anybody, there's rep for that.
    – Tester101
    Commented Mar 28, 2012 at 20:23

2 Answers 2


Get the water tested first to determine the source of the smell.I would test three samples,out of the well but before the softener,after the softener but before the tap and at the tap.This will isolate each componant as the source.Don't forget the fridge door dispenser if you have one.The smell may not be evident until it absorbes oxygen from the air.


If the smell is a rotten egg odour, this is caused by hydrogen sulfide, and is a very common issue.

It is hydrogen sulfide gas that causes the smell, and so likely well i's sitting in a bottle the gas is coming out of the water and concentrating in the top of the bottle, hence the noticable smell. It is likely that your water has a bit of a smell normally, but you've become desensitized and used to it, or it's simply at a level that isn't noticable.

You can get hydrogen sulfide test strips to check your water. As @mikes says, check from a tap before any treatment (there should be one on your pressure tank) as well as after.

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One of the common ways to treat it is with an activated carbon filter. You should however consider a getting professional opinion, as it is often better to treat the source and not just the symptoms. There may be more problems, or a better solution. Be careful though: the water treatment industry is full of people that don't know a whole lot but are willing to sell you equipment, especially equipment that requires regular servicing or buying bags of salt. Any reputable company will want to have a lab analysis done on some samples prior to actually installing any equipment. They need it at the least to figure out how big of a filter to put in.

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