Stale Hot Water

January 3, 2004 10:24 AM

My hot water smells moldy (more inside)..

We just got back from a ten day vacation at the beginning of this week. I took a shower the next morning, and distinctly smelled mold. I was worried, because I thought the shower stall was leaking somehow. But then we noticed the smell at other faucets in the house (kitchen, other bath) if we used the hot water. It's been a couple days since we've been back, and there is a faint smell, still. The water looks clear. The water heater is 5-6 years old, and I've done nothing to it since it was installed. No visible signs of damage on the heater. We are located smack-dab in the middle of Austin Tx suburbia, so we're on city water.
Has anyone heard of this? Is this dangerous to us to bath, cook, wash dishes with it?
Any ideas how to remedy this? Things I've thought of:
- adding some bleach to the hot water tank
- draining the tank completely
- cranking up the heat (gas) on it (not sure what the current temp is, but it's hot enough to hurt if you run hot only)
I looked on the web, but I couldn't find anything like this.
Thanks in advance, AskMetafilter!

posted by j to health & fitness (8 comments total)

Where did you go? Your water may have not changed., where you went may have been better than yours.

Do you know your neighbors? Go next door and smell their water or have them smell yours.
posted by thomcatspike at 10:49 AM on January 3, 2004

If you've only been back for a couple of days, it's possible you haven't cycled through an entire tankful of water yet. Perhaps either draining it or letting it run is the best course of action. Or is it possible that the problem has been there before, but you failed to notice it until a long absence from the familiar scents of home?
posted by majick at 10:51 AM on January 3, 2004

Water that sits in hot water tanks can sometimes get that moldy smell. When I have been away for a while it happens to me sometimes. I usually just open the pipes, turn the heater up and let it all run out for a bit. You can also flush the system with bleach [I haven't done this] though some people think you should get a professional to do this part for you. Draining and flushing a hot water tank is not super rough, depending on where the tank is located and might be a good for maintenance on the tank as well. According to some websites I've read, if the city did any hydrant flushing [unlikely, I know] the gluck from that can wind up in your tank.
posted by jessamyn at 11:17 AM on January 3, 2004

I recently had our hot water heater replaced, as it had a tiny gas leak and was original with the house (30 years old, in north Austin). I'm guessing it was FULL of calcium deposits, etc.

Our water quality improved greatly when we did so, although it cost almost $1K with it being done on a weekend and the other work it took to bring it "up to code".

I'd go along with the suggestion to run the tank "dry" then see if it improves.
posted by mrbill at 12:59 PM on January 3, 2004

thanks for all the advice/comments, everyone.
thomcat - we were in Belize, the water quality (I hope!) is better in Austin.. unfortunately, we live in a neighborhood with not-so-friendly neighbors, so I would feel uncomfortable going to their house and smelling their water too :)
majick - We probably haven't cycled through the water yet, we don't use that much hot water (I do the laundry in cold water) -- I think I should probably do as jessamyn (thanks for the link!) and mrbill suggest..
but as to now-unfamiliar-smells, I might agree with you -- that being away for a while changed the familiarity -- but I am "blessed" with a bizarre ability to smell things that no other human can seem to smell, so I think I would have picked up on it before we left (S.O. can smell the water funk too, so it's not just me), but you may be right..
I'll definitely try draining it tomorrow morning..
posted by j at 3:02 PM on January 3, 2004

Putting bleach directly into your hot water heater=really, really bad. Unless you flush it all out, which you'd probably need a professional to do, you'd essentially be bathing with bleach water until it dissipates. That can be really bad for the hair and skin and, umm... life.

In addition, bleach will not work as well against calcium, lime, and rust- the major things that would corrode and slow down your plumbing. CLR is good for drain openings, but for the actual heater I would call a plumber.

Actually, I wouldn't call a plumber either, because if everything worked fine before you left, massive rust didn't develop over such a short time. The answer lies in "10-day vacation." You probably don't smell mold, but rather the musty odor of rust that accumulated in standing water left in pipes. Ever gone to a bar and ordered a draught beer that no one else ordered for a really long time? You've got the plumbing equivalent of "left-in-the-tap runoff."
posted by XQUZYPHYR at 4:07 PM on January 3, 2004

Just for the sake of completeness (if anyone searches on this topic), here is what I decided to do:

I drained the tank through a faucet in the kitchen (until the water ran cold -- yes, I know this isn't really draining it).
I also removed quite a bit of cruddy-looking water from the spigot at the bottom of the tank until it ran clean.
Neither of these helped our stench.

I waited a while, hoping it would go away. But I ended up adding bleach (1/4 c.)
(I had read a book recently that said to add a drop or two of bleach to drinking water to decontaminate it. I figured 1/4 c. is about the same amount in a 30+ gallon tank.)
The water now has no odor!
I've been bathing in it, eating near it, etc.. and I haven't died yet. Only thing is, I'm now a blonde. (okay, not really)
Thanks to everyone for all of their answers.
posted by j at 8:40 AM on January 20, 2004

Just for the sake of completeness (if anyone searches on this topic), here is what I decided to do:

I drained the tank through a faucet in the kitchen (until the water ran cold -- yes, I know this isn't really draining it).
I also removed quite a bit of cruddy-looking water from the spigot at the bottom of the tank until it ran clean.
Neither of these helped our stench.

I waited a while, hoping it would go away. But I ended up adding bleach (1/4 c.)
(I had read a book recently that said to add a drop or two of bleach to drinking water to decontaminate it. I figured 1/4 c. is about the same amount in a 30+ gallon tank.)
The water now has no odor!
I've been bathing in it, eating near it, etc.. and I haven't died yet. Only thing is, I'm now a blonde. (okay, not really)
Thanks to everyone for all of their answers.
posted by j at 11:32 AM on January 20, 2004