Diagnosing a water heater leak (for dummies)

If you know a lot about water heaters, stop reading. If you're like us -- water heater quasi-dummies, especially when it comes to leaks -- read on. 

Yesterday we spent $99 to get educated from a pleasant George Morlan Plumbing guy about why what we thought was a leak in our water heater, almost certainly wasn't. 

A few days ago my wife noticed water pooling around the tile floor in front of our water heater. Not a huge amount, but quite a bit. She put towels around the water heater.

When I got home, I had the bright idea of putting paper towels around the bottom of it, so we could identify where the leak was coming from. None of the inlet/outlet fittings, overflow tube, or drain valve were leaking.

And the leak wasn't constant. It came and went.

In fact, the evening before the day the George Morlan guy was going to come out and check the water heater, I told my wife "We should call them and cancel the appointment; we're going to look like fools, plus pay $99 for a service call, since there's no longer a leak."

But an hour or so later, some of the paper towels were wet again. Leak! I was happy, because now, when the doorbell rang the next morning, I wasn't worried about letting the guy in. We had a real problem!

Well, not really. What we learned in the next half hour, at that cost of $99 was...

(1) Water heater leaks don't stop and start. (Sort of obvious, but, hey, we're water heater dummies.) Once a leak begins, it'll continue.

(2) A leak will be obvious when the access panels to the temperature setting, etc. are removed. Because a tank always is full, a leak will distribute water all around the outer lining of the tank. The guy felt the insulation under both access panels. Bone dry. No leak.

(3) At first he thought we might have a drainage problem, water coming into that corner of the house from outside. But I peered over the top of the water heater with a flashlight. Also bone dry. Water wasn't coming through the wall.

(4) Last possibility, which probably was the culprit: condensation. The tank rests on a metal bottom. My wife was able to push a thin duster under the small space between the tank and floor. It came back damp. The George Morlan guy said there's a roundish opening in the middle of the tank, used in transport or something. Water could have condensed there and flowed outward to the utility room floor. Strange, because this had never happened in the twenty-two years we've lived here. Maybe a rare meteorological condition, combined with doing laundry, or whatever.

(5) As long as he was there, I asked another question that I'd been wondering about: should a water heater be drained regularly? He said, "No, there's no need." I told him that I occasionally hook up a hose to the valve at the bottom of the tank and drain a couple of gallons from it. Since we're on well water, usually there's some crud that comes out. He said newer tanks stir up the tank water in such a way, even that now isn't necessary.

So we learned some stuff about water heaters. Worth the $99, I guess.

Good news is that we have a 10 year warranty on our six year old water heater, so if there really is a leak (which seems unlikely), we'll get both the $99 back and a new water heater.

Anyway, the key tip was to check under the access panels for wetness if a leak is suspected. Somehow I thought the inside of a water heater had seams, but this isn't the case. Thus a leak anywhere leads to water all around the outside of a tank (under the outer cover, that is). 

Comments

[Dan Gellner]

I'm surprised he didn't check the emergency check valve, which is a brass looking valve on the side that typically has a pipe of some sort that faces down to the ground. I've seen on older houses, this pipe will often exit through the side of the house to the outside as well. Over time, that valve can go bad, seal inside degrades or cruds up. It's designed to open in the event that the pressure in the tank reaches a dangerous level. I've seen instances where if the pressure valve doesn't function the blast from the explosion launched the water heater out of the house like a rocket leaving a silo, and ended up across the street in the neighbors yard.
Anyway, if the seal is compromised, it will leak. Sometimes not at all, some times a stream. It depends on if the water temp is at rest or if it is actively heating to catch up. So if it has been a while since hot water was used in the house... It's probably idle and maintaining a set temp. If you take a shower, and it drains and puts a bunch of cold water in there, the heat kicks on, and it will go until it gets the water to the temp, and a little beyond. That is most likely the time it will leak noticeably.

I would think it strange that after 20 years, you hadn't seen the meteorlogical conditions that just happened and all of the sudden it leaked.

[Perry D. Farmer]

Actually I am a little concerned about the plumber. He is somewhat correct about the requirement about draining off a few gallons but the fact that you do get crud out the bottom indicates that the piping inside is not 100% effective in this regard. Also any crude that does get stirred up can end up in your faucet screens and plug them up. Typically leaks at at the penetration points and their welds. The pipe inlets and outlets and the heaters at the access panels. These can and do leak and typically will flow down the edges to the bottom and wick up via the insulation. If the outer cover was sealed then a full tank would get the insulation wet with a leak but the outer cover is not a sealed unit. Condensation is somewhat rare but possible under heavy use if outside air comes in contact with the cold tank while filling with cold water. I would check the boiler drain valve for leakage which is common since the seat can get partially plugged with your crude and not seal all the way. I would also check the relief valve piping including joints. It is suppose to be piped outside in most cases and should be dry. This valve can have issues sealing and you can usually reseal it by manually opening it and letting it close on its own. If it continues to releave replace it but also this could be an indication that your source pressure is to high. Also a leak will sometimes go away depending on your source of water. Inside an older tank and the pipes connected to it is a film from the minerals in the water as the unit ages. If this peals away during heavy use where a leak is present it may seal itself when the use stops. I have witnessed many of these during my 35 years as a power plant operator in hydros, coal fired, as well as gas turbine operations in water heaters, misc. piping, as well as heat exchangers. Water leaks are temperature affected so pay attention to your use when the floor gets wet.

[Brian Hines]

Perry and Dan, thanks for the great info. Our water heater's release valve doesn't seem to be the problem. The release tube drains into a sink. Plus, the area around the valve on the top of the tank is completely dry.

I agree that it seems unlikely we'd suddenly get condensation when this hasn't happened in the six years we've had this heater. Possible, but unlikely. The theory of a small hole covered with film that got uncovered temporarily makes sense.

Our well water is bad, but is treated with some sophisticated equipment. Still, it has some minerals and salt from the softener. Good news is, the leak was so minimal, probably we'll have time to deal with it without water damage if it happens again.

The plumber guy thought draining a few gallons out periodically was fine, if done regularly. He agreed with me that very occasional draining isn't smart if you are on a well with poor water quality.

I told him my story of how, after we moved into this house twenty two years ago, I decided to drain some water from the water heater that had been used by a couple (with minimal water treatment) for a long time.

Can't remember exactly how I was going to drain some water. Probably by putting some in a bucket, given what I remember. Or maybe with a short hose into a floor drain. Anyway, I opened up the valve and a flood of what probably was magnesium grit started coming out.

It instantly gummed up the valve, so I couldn't close it. The utility room quickly filled up with disgusting black gritty water. It was a mess. Lesson I learned was that if you're going to open the drain valve on a water heater tank, do it regularly if grit is accumulating in the bottom. And/or have a long hose attached so you can drain the entire tank outdoors if something goes awry.

[mogodia]

I have the same EXACT symptoms-everything dry!
But floor is wet & leak from under the metal bottom of tank ONLY after showers & loads of wash...then a little lake appears on the floor. In part 4 about condensation: I guess this is what we have too. So what is the fix for condensation that occurs when tank is heating up?? -many thanks in advance

[Hilda Nelson]

We have some type of leak we can't find. Water meter runs off and on and recording gallons and gallons of water usage, but no sign of wetness anywhere. This morning we discovered that the incoming line is 'warm' and the outgoing line isn't as 'warm'. Anybody know what that means ? ? ? ?

[michelle]

Overflow pipe on waterheater is constantly running & its all very hot water. What can it be?

[Amanda]

Hilda Nelson same thing happend to me it was a busted hot water pipe under my home water heater was running every so often could hear the water flowing but couldn't see it any where till my uncle went under my house and it was like a sauna under there even floor boards were starting to warp

[Adele Masterson]

My first reaction will be turn off the water heater then investigate for the safety of the person who will check it.

[Martin Morrison]

We have the same problem. Only leaks at certain times: But It's all blanketed and we live in a really low humidity area.
Also, the amount of water could never be attributed to condensation.
In case this is common to a certain brand/model I'll report mine.
GE Smart water heater mfg by Rheem under model SE50T12AA01 .
I thought it was longer ago than it was that I put it in. It says it was made in 02/03 and has a 12 year limited tank and parts warranty.
I think I'll try to see if Home Depot will honor the warranty.

[Bill]

Got some water around tank yesterday, insulation material dry, turned off water to tank. Today turned water supply back on, no water around tank after several hours, seems like leak stopped.
GE water heater model SE50T12AAH 50 gal 12 yr., purchased 11/2006 at HD. Similar model

[Nina Holmes]

I have a slight amount of water, mainly dampness, under water heater and furnace. Called plumber, I'm on "the schedule" for 2mrw. But, is this in fact a plumbing problem? The water heater? or the furnace? It's a WH: Whirlpool 50-gal tank, 6-yr warranty. Bought house in 2005 and 1st problem we've had. Any suggestions? Should I cancel plumber? Thanks

[Chris]

I have a brand new water heater, the old one and the new one doing the exact same thing... water around the bottom of it, and it almost seems like its dripping from the relief valve. The water isn't warm. Could it be due to the venting of the heater itself? I had some issues with a dryer vent and had to have my HVAC guy come out and clean out the vent line.. I'm stumped and literally the unit is a couple months old..

[Tim]

A lot of these comments make it sound like condensation is the culprit. It happens but most often there's a leak at the pressure relief valve. Waterheaterhub.com has a good page on diagnosing where the leak is actually coming from.

[juan]

I have a leak coming out of the top of my heater and out of a pipe purposely deaigned to go out but leaks a good bit of water when the hot water is on. But when closed it stops is that normal?

[carl]

My water heater was leaking and now doesn't

[andrew]

Hi juan
sounds like you have a lot of pressure in the tank, release the pressure via the TP valve this should help . check out this article for more information on your water heater pressure relief valve. http://www.h2ousegeek.com/water-heater-pressure-relief-valve/

[Bonita Kent]

My GE Smart water is leaking on the two pipes on top of the heater. Each pipe has a faucet on it. There is also a brass looking tab that spins. Which do I use to turn it off?

[Sheila]

I started flushing my tank, before I turned the power off and I didn't turn the water off either. I only drained it for about 5 minutes now the drain in dripping. It did not drip before. Should I now flush and drain the heater the correct way... Or just leave the d@&; thing along like my husband says. It's a GE electric hot water heater. And hope that it stops dripping around the drain valve

[steve ortkiese]

I have a lifetime electric water heater I bought at Lowes in 1996. It was manufactured in Johnson City, TN. I started seeing water pooling around the bottom 2 weeks ago. Seemed like a small leak. I called the manufacturer
About it and they asked me to check all the usual places. Everything was dry except for the bottom. They asked me take it back to Lowes and have them return it. They gave me a return authorization number. I went ahead and ordered a new lifetime Westinghouse water heater. It arrived and I was going to swap it out. The leak is now stopped. Hard to believe it was condensation, but what else? Piece of trash plugged the hole

[Lmp]

My hot water heater sounds it is running my bathroom floor is warm near toilet what does this mean