My hot water heater is leaking.

April 6, 2009 8:24 PM

My hot water heater is leaking a very small amount of water. It looks like it only happens when hot water is used. Who do I call about this and how serious is this?

A few questions related to this:

What could be causing this?
Who do I call about this?
How soon do I need to take care of this?

(I only say this because I am insanely busy at work and would like to put this off as long as possible.)

posted by hazyspring to home & garden (25 answers total)

It would help if you specify where the leak is coming from.

If it is from a hose/pipe connection then that's not too bad. If its coming from a random place on the body of the heater, then you might have a bigger problem.
posted by Dave. at 8:34 PM on April 6, 2009

You an owner or a renter?

If you're a renter, you call your landlord. If you're an owner, you call a plumber.

Is it serious? Repeated exposure of structural wood to water is always serious.
posted by Chocolate Pickle at 8:43 PM on April 6, 2009

Also, small leaks are quite likely to become big leaks if left untreated.
posted by Chocolate Pickle at 8:43 PM on April 6, 2009

Water heater tanks have only a finite life before they fail. Different models will have different year warranties, with longer ones being more expensive. Generally, the tank lasts much longer than the warranty period, but it eventually rusts through.

The small leak is a big clue that the tank is on its way out and could go at any time, making a huge mess as gallons of water go everywhere. You want to call a plumber, and sooner rather than later. When it happened to me it failed about a month after my dad noticed it leaking. You might have days or weeks or even a month or more before it goes, but not a year. Putting it off is only going to make it a much bigger issue to deal when it does fail.
posted by 6550 at 9:09 PM on April 6, 2009 [1 favorite]

Is a pipe coming out of the tank leaking? Is the tank itself leaking?

If the former, see if you can fix it, or give up and call a plumber. If it's the latter I guess a trip to Home Depot is in order.
posted by floam at 9:18 PM on April 6, 2009

Having gone through this pretty recently, I'd second 6550 - yours may not be going, but there is a good chance it is going, and they do tend to go big, as in many gallons of water on the floor overnight. This is I gather a pretty common outcome with water heaters. If it's quite old you might just consider getting it replaced, which would cut it down to just one service visit - but it could be something minor, in which case you'd be wasting money: however if you get someone out to look at it they won't be prepared to deal with it if replacement is the only option.

When I had this done they literally came the same day, pulled out the old one, installed the new one, and carted off the old one and I was wrapped up before noon. I had a deal through my gas company though who arranged it, I don't know how much of a difference that made. It wasn't terribly expensive (I forget the exact, several hundred, less than five hundred).

I say deal with it, it's the only chance you'll get to deal with it on your own terms if it is headed towards total failure, and there's no other way to be sure without getting it checked.
posted by nanojath at 9:24 PM on April 6, 2009

It could be very serious, and is likely not benign. Water heater failure can cause catastrophic flooding. The good news is that the internals usually rot out giving you crappy hot water long before the tank starts leaking. This is time to call a plumber and perhaps even time to isolate the hot water heater from the water supply.
posted by caddis at 10:49 PM on April 6, 2009

6550 's answer is exactly in accord with the advice I've gotten from a friend, who knows what he's talking about, on the same topic. Failing tanks often dribble briefly before letting loose. When they let loose, it's not pretty. If you must put something off, choose something else.
posted by jon1270 at 10:59 PM on April 6, 2009

It is possible that there is nothing wrong with your water heater. There is a pressure relief valve on top that may be releasing water because your primary water pressure reduction valve for the house is worn out. The fact that the leak is intermittent suggests this. In this case the water pressure in your whole house could be dangerously high. Put a bucket under the open pipe coming from the pressure relief valve on top of the water heater, and if that's where the water is coming from, then replace the main PRV, and you'll be back to normal.
posted by weapons-grade pandemonium at 11:10 PM on April 6, 2009 [1 favorite]

Turn off the water NOW.

(hopefully there's a valve near where the cold water goes into the water heater.)

Then call a plumber.

Now that the water is turned off, when it suddenly becomes a much larger leak you'll have 30 gallons of water on the floor instead of hundreds.

For extra credit, you can drain the water heater using a hose and some buckets (or a drain) while you wait for the plumber.

(Yes, I have had this happen, twice. Don't mess with water heaters. Trust me.)
posted by mmoncur at 11:11 PM on April 6, 2009

For extra credit, you can drain the water heater using a hose and some buckets (or a drain) while you wait for the plumber.

This is not a good idea if it's electric unless you cut the power first. The heating elements in an electric heater will burn themselves out if they're exposed to air while still on.
posted by TungstenChef at 11:53 PM on April 6, 2009

Yes, certainly turn it off first. Gas or electric. Be warned that the change in pressure as it cools down could make the leak worse, so plan to drain it ASAP.
posted by mmoncur at 1:12 AM on April 7, 2009

As everyone has said, you need to identify where the leak is coming from.

If it's actually from one of the pipes coming into or going out from the tank, that's usually an easy fix...most likely a loose or failing connection.

If it's just mysteriously appearing around the base of the tank...big problems. You will be looking at replacing the water heater. Soon. Like...today. Before the tank lets go. I replaced my ancient water heater a couple of years ago. It was leaking around the base. After draining, the guy hauling the tank away went to lift the unit up on his truck and the entire bottom of the tank fell off in a rusty mass.

Water heaters have a pressure-relief valve on the side of the tank. It usually has a short pipe attached to it extending down along the side of the tank, but not always. Is the "leak" you see actually dripping out from this valve? If so, there are a variety of problems that can cause this. The valve itself may be failing. Or, in the case of an electric tank, one of the heating units may be malfunctioning, causing over-heating of the water and raising pressures in the tank.
posted by Thorzdad at 5:52 AM on April 7, 2009

Are you sure it's not condensation? When the pilot light of my water heater goes out and the water cools off, when it gets restarted, the moist air from the burner condenses against the inside of the tank and it dribbles and hisses for a few minutes.
posted by gjc at 6:03 AM on April 7, 2009

Could very well be the pressure relief valve. Ours spits out a bit of water now and then; we just leave a small metal bowl underneath the pipe to catch the drips. Our cats drink out of it. It's never leaked more than about a cup or so at a time, so we don't worry about it.
posted by caution live frogs at 6:16 AM on April 7, 2009

How old is the heater? If it's several years old, then this is your "Hey! The water heater is about to go kaput!" warning. It could be a leaky pipe, or a drip from the pressure relief valve. But if you're not absolutely sure, call a plumber. A $400 water heater replacement might indeed suck if that's what's needed, but it's infinitely preferable to a floodocalaypse.
posted by azpenguin at 8:19 AM on April 7, 2009

Isn't this Spring run-off season in Buffalo? Water supply systems are probably topping up their storage systems there now, and this can maximize pressure delivered to your house, if you are gravity fed and unless your utility has a more sophisticated system than mine does. That would make it more likely that your pressure relief valve would dump some water out.

I'd say you could wait to see if it continues.
posted by jamjam at 9:13 AM on April 7, 2009

How old is the water heater. If it's just a few years old, maybe the leaking isn't urgent. Still, the thing shouldn't be leaking.

I had three water heaters in the time I owned a house. They each lasted about nine years. Each of the two times I saw a little water on the floor, it was time to change the water heater. It doesn't take all that much time, but it can be pricey. I seem to remember $700-900.

I've helped a couple people who ignored the water and suddenly had a flood in the basement. Don't wait too long, or you'll have a mess.
posted by Elsie at 9:55 AM on April 7, 2009

If you do have to replace your existing heater you might look into a high efficiency unit. There are some pretty decent tax breaks available and over time you can end up saving a lot of energy and money. Also, these units vent through the wall, not a chimney and you may be able to reclaim some space in your house now or at a later date by taking out the chimney.
posted by caddis at 10:03 AM on April 7, 2009

Could very well be the pressure relief valve. Ours spits out a bit of water now and then; we just leave a small metal bowl underneath the pipe to catch the drips. Our cats drink out of it. It's never leaked more than about a cup or so at a time, so we don't worry about it.

You should worry about it. This happened to me because the main PRV was worn out, and the pressure in the whole house was dangerously high.
posted by weapons-grade pandemonium at 10:35 AM on April 7, 2009

For extra credit, you can drain the water heater using a hose and some buckets (or a drain) while you wait for the plumber.

Having been through this a month ago, I can cite another reason why this is a bad idea. If your water heater hasn't been drained regularly over its lifetime, you've got a lot of mineral deposits in the bottom of your tank. (That's the purpose of draining regularly -- to get rid of these deposits.) And if you live in an area with really hard water, like I do, that raft of mineral deposits could be six inches thick. If your tank has started leaking (and it sounds like it has), the little pinholes that have formed will generally grow and grow, until the bottom of your tank eventually rusts through and falls out, leading to the flood others have mentioned. Right now, the mineral deposits in the bottom of your tank might actually be slowing the leak -- plugging the holes.

So don't drain your tank. Could make things worse in the very short term.

And call a plumber, pronto, to find out how bad the leak is. Once the tank starts leaking, the water heater needs to be replaced. Period.
posted by mudpuppie at 10:36 AM on April 7, 2009

Our Vaillant combi-boiler sprung a leak recently, and similar to your experience only leaked when water was being drawn. I immediately turned off the unit and called the plumber who does our annual service. Turns out that we'd somehow let the water pressure drop out of the required zone, and there was a small amount of seepage around the seals.
He talked me through turning a couple of taps on the underside to add more water perssure, and lo - the leak stopped.

I was paranoid that it was going to go everywhere, so I'd definitely give a plumber a call - make sure you have the make/model/year of boiler at hand - as it sounds like it could be any one of a number of things...
posted by Chunder at 12:38 PM on April 7, 2009

Ok, I was afraid of this. I will call a plumber ASAP. Thanks.
posted by hazyspring at 5:06 PM on April 7, 2009

First thing the plumber should do is check the water pressure in the house. This will indicate if the main PRV is worn out or needs adjusting.
Don't let him sell you a water heater if you don't need one.
posted by weapons-grade pandemonium at 7:28 PM on April 7, 2009

As a follow up, I did wait longer than I should have, the leak started getting worse. But, I did have plumbers come out and replace it. Turns out it was 18 years old!

When they started to drain it, it was completely rusted and the top broke off, so they said that it was a good thing I didn't try to drain it myself, because I would have had water all over.
posted by hazyspring at 12:56 PM on May 7, 2009