Water Heater Leaking: What should you do?

A water heater leak may seem like just a minor nuisance, but it can quickly turn into a big problem. Even a small amount of water will cause damage to your floors, sub-floors and walls. Keep in mind that water heater leaking may be a symptom of a much larger problem. In extreme cases, a catastrophic and complete water heater failure can cause a significant flood that could lead to hefty repair bills and damaged personal property.

Water heater leaking can also be a health concern. Damp and wet areas can sprout mold and mildew that can cause allergic reactions and asthma in some individuals. According to the EPA, some mold spores are toxic and can lead to serious health problems.

A water heater leak does not shrink or go away with time. It only gets worse, so it’s best to move quickly to fix the problem.

Water Heater Leaking Step 1: Determine whether your water heater is the source of the leak

Not every small puddle of water found at the base of a water heater is necessarily due to a leak. A water heater and the pipes around it, plus the other appliances typically found nearby, can form condensation, which can accumulate and drip to the floor; especially in a basement or during damp weather.

Furnace drain lines, water softener discharge lines and other plumbing can also be the cause of the leak. If a small amount of water is noticed under or near a water heater for the first time, wipe it up and try to determine its source through simple observation. Closely inspect the water heater and its plumbing fittings for obvious signs of water leakage. If none are found, inspect other nearby possible sources. Water faithfully obeys the laws of gravity, so pay particular attention to anything directly overhead, especially water pipes.

If still nothing is found, lay down some paper towels over the area that was damp and come back to check on it every few hours. If, after a day or so, the problem does not re-appear, it’s likely nothing to be concerned about. If, however, water does show up again and no other source for it can be readily identified, the water heater leaking is the likely cause, and the inspection steps that follow should be carried out

Water Heater Leaking Step 2: Turn off the power to your water heater

Once you determine that your water heater is leaking, the first thing you should do is turn off the power supply.

If you have an electric water heater simply locate your circuit breaker box and switch off the breaker for your water heater. Water and electricity can be a dangerous combination, so it’s important you do this before going forward.

If you have a natural gas water heater, it should have an on/off switch or dial. Make sure it is set to “off”. Avoid closing the gas shut-off valve if possible. These valves can be finicky and susceptible to failure over time, so it is best that they be left alone.

Water Heater Leaking Step 3: Turn off the water supply

WARNING: Water heaters are typically factory-set to heat water to 125° F, which is hot enough to inflict first degree burns on skin on contact. When turned all the way up to maximum temperature (which can be anywhere from 160ºF to 190º F) serious injuries can result from even indirect contact with the water. Always take precautions to avoid coming into contact with heated water.

If the water heater leaking is significant and obvious, turn off the water supply at the cold water shut-off valve.

Most water heaters will a valve located above the water heater (by code they are required to be here) that will shut off the water supply. This valve will either have a handle that you have to pull down, or a gate valve (essentially a dial) that you will have to turn clockwise to close. Before closing the valve, make sure you can get to it safely without coming in contact with any water. If you have a large, serious leak and cannot reach the water shut-off valve safely then you should find the main shut-off valve for the house and close it to stop the water supply to your water heater. Shutting the water off should slow and may even stop the leak depending on where it is coming from.

If the actual leak source is not yet identified, leave the water supply on for the time being, to assist in locating it.

Water Heater Leaking Step 4: Determine the location of the leak

There are a number of problems that can cause water heater leaking, so it’s a good idea to perform a quick inspection. A proper diagnosis of the leak before calling a professional will make it easier for them to solve the problem.

  1. The cold water inlet and the hot water outlet connections: Check the points at which the inlet and the outlet pipes connect to the water heater at the top of the unit. A leak here, if minor, may require no more than the tightening of a loose connection with a pipe wrench and is likely very fixable.
  2. The temperature and pressure relief valveEvery water heater has a temperature and pressure relief valve located on the side of the tank with a pipe running down to the floor. This valve is in place so that in the event that the water is heated too much, or there is too much pressure in the tank, the valve will let water out of the tank to relieve pressure. Inspect the point at which it enters the tank, on the side of the water heater near the top, to see that it is watertight. Also inspect the valve itself. If this is the source of the leak, then water will be flowing down the plastic pipe attached to it when the valve is in the closed position. This means that either the valve is defective, or it is working properly and excess pressure inside the tank is forcing it to open. A leak from this location is usually fixable, but is also cause for concern.
  3. The heater drain valveCheck the drain valve, located near the bottom of the tank. Make sure that it closes (and is closed) completely, and that its point of entry into the tank is watertight. A leak from this location is not a serious problem and can be fixed.
  4. The bottom of the hot water tankSince the tank itself is wrapped inside insulation and is enclosed in an outer skin, any leak in it will not be visible from the outside. If your water heater has an internal leak water will likely escape at the bottom of the tank. Most water heater leaks are from the tank itself, and are due to age and deterioration. If this is the case the only fix is to replace the water heater.

Water Heater Leaking Step 5: Repairing or replacing

As stated above, water heater leaking can be a serious problem, so take action quickly. Depending on the type of leak you have, you will either have to repair your water heater, or replace it. In both cases, it is highly recommended that you call a professional plumber to deal with the problem. Improper repairs or removal of a water heater can cause larger leaks and even floods which could lead to much more serious problems. A professional plumber will be able to take care of any issue your water heater has.

Still unsure about some of the information discussed in this article? Try watching this video:


Water Heater Leaking: How to fix a leaking water heater

Water Heater LeakingIf the problem appears to be minor, and you have experience doing your own home plumbing repairs, you may choose to fix your water heater yourself. Your next course of action will depend on the source of the leak.

WARNING: Repairing water heaters can be difficult. Improper repairs of a water heater can cause larger leaks and even floods which could lead to much more serious problems. If you do not have any experience doing home plumbing repair it is highly recommended that you call a professional plumber to deal with the problem.

Is your water heater leaking from the cold water inlet and the hot water outlet connections?

Check the points at which the inlet and the outlet pipes connect to the water heater at the top of the unit. A leak here, if minor, may require no more than the tightening of a loose connection with a pipe wrench. Anything more significant than that will require a professional repair.

Is your water heater leaking from the temperature and pressure relief valve?

A leak from the temperature and pressure relief valve (T&P valve for short) may be caused by excessive pressure inside the tank or overheating. This pressure on the T&P valve will keep it open almost continuously, leading to water heater leaking. To see if this is what’s causing the leak, reduce the temperature of the water by lowering the thermostat setting. Turn the water and power/gas to your heater back on and observe it for a period of time. If it continues to leak shut everything off immediately.

If you determine excessive pressure or overheating is not causing the problem, then you may have a faulty valve. Put a bucket or container under the discharge tube and open the T&P valve by pulling the tab on the valve up so it’s pointing straight out. This will flush the valve out and remove any debris that may be causing it to work improperly. If after flushing the valve it is still leaking you will need to replace it.

Before replacing the T&P valve you’ll need to drain your hot water tank. If you’re unfamiliar with how to do this, read Water Heater Maintenance: How to maintain your water heater. There’s no need to empty the tank completely. Just ensure the water level is below the valve. To check this, simply open the valve. If no water comes out then the water level is below the valve.

Once your hot water tank has been drained, go to your sink or bathtub and open the faucet on the hot water side to let air into the tank. Then, grab the T&P valve with a pair of channel locks and turn it counter clockwise until the valve comes off. Take your new valve and wrap the threads with Teflon tape four or five times (this will help seal it against any leaks). Make sure you wrap it tightly and work the tape right into the grooves. After this is done, screw the new valve into the water heater, using the channel locks to turn it three or four times until it is securely in place.

Once the new valve is in place you can turn on the cold water supply to refill the hot water tank with water. Do not turn the power to the heater back on until the tank is full. Check the sink or bathtub faucet you previously opened. When water is coming out of it at full stream you know your tank is full and you can turn the power back on.

Make sure to attach a discharge tub to your new T&P valve. This ensures that any hot water released by the valve goes down to the floor and does not spray outward.

Still have question about how to replace the T&P valve? Try watching this video:


Other Possibilities: If water is leaking from the threads of your T&P valve then remove the valve as per the instructions above. Check for any rust or corrosion on the tank. If there is any rust or corrosion your water heater will need to be replaced. If the tank appears to be in good condition, wrap the threads of the valve in Teflon tape and screw it back on to the tank. Observe your water heater for a period of time to see if this solves the problem.

Another cause of a leak from the T&P valve could be high water pressure in the municipal system or some sort of backflow preventer around the water meter or main shutoff.  If you remove your T&P valve and see no signs of corrosion inside the valve then this may be the case. You’ll need a licensed plumber to diagnose and handle these problems.

Warning: NEVER plug the temperature and pressure relief valve to stop a leak. This valve is an important safety feature on your water heater. Plugging the valve will void any warranties your water heater has. More importantly, it could cause your water heater to explode.

Is your water heater leaking from the heater drain valve?

A leak from the heater drain valve may be caused by debris inside the valve or a faulty valve (similar to the T&P valve). Place a bucket or container under the valve and turn the dial counter clockwise to open the valve. This should flush out any debris. If after flushing the valve it is still leaking you will need to replace it.

To replace the drain valve, drain the tank completely and follow the same steps outlined above for replacing the T&P valve.

Tip: Unlike the T&P valve, the heater drain valve is not a safety feature. If you are unsure about replacing the valve yourself or don’t have time to get to it right away, simply buy a brass garden hose end cap and screw it onto the valve threads. This should stop the leak.

Is your water heater leaking from the bottom of the tank?

This suggests a serious internal problem and it is likely your water heater needs to be replaced. Do not attempt to disassemble your water heater and perform internal repairs. If your water heater is leaking from the tank either call a licensed plumber to inspect it further or replace the water heater.

Is your water heating still leaking after repairs?

Water heater leaking can be the symptom of a more serious problem, so keep a very close eye on your water heater after performing any repairs. If after attempting to fix the problem there is still a leak shut the power and cold water supply to your water heater off immediately and call a professional plumber.

photo credit: Rob Ireton via photopin cc

46 thoughts on “Water Heater Leaking: What should you do?

  1. charmingj on said:

    This info was very informative thats guys your the best. I found a split in the cold water pipe . I cut out the split replaced it with new pipe short piece with two couplers on each 3nd .

    • I have the same problem. No other leaks. T&P valve works when manually used. Have drained, refilled, turned heat down a bit but a couple days later hot water drains out the metal pipe outside after showers. Is this a backup release?

      • Replaced T&P valve on heater to no avail. I found a second T&P valve in the ceiling of my garage below the sub-flooring in my split-level home after seeing a 4″x4″ cutout in the ceiling. Had to cut out a much larger area to access with a pipe wrench. This was connected to the pipe running outside referred in my original comment above. Replaced it and haven’t had a problem since.

    • Water Heater Leaking Info on said:

      It should be ok, although depending where the leak is you may still have a slow leak. You could always drain your water heater to make sure there is no water leaking out while you leave it.

  2. Emil Mian on said:

    my heater is leaking from top. Right around pipe leading into the tank. Top of the tank is corroded from the areas surrounding this pipe, going out about an inch or so. Remainder of tank appears ok with regards to corrosion. Can this be saved? If so, How? T^hank you much

    • Water Heater Leaking Info on said:

      Generally any sort of corrosion means it’s time to replace a water heater. Have a professional plumber take a look at it though just to be sure.

  3. hello – thank you for the informative video – very helpful! however; my water heater is leaking from the vent. It’s dripping from what looks like a hat coming off the pipe that leads to the chimney. Could that be from all the rain we’re having? Never happened before but we have no hot water. Any suggestion would help! I don’t have money to call a plumber at this time…

    • Water Heater Leaking Info on said:

      Try turning off the water supply. If that stops the leak then your tank is seeping water and you will likely need to replace it. If it doesn’t stop the leak then it might just be a condensation problem.

      How old is your water heater? If it’s older than 8 years then it’s more likely to be a leak.

  4. thank you for your help. My heater was only 5 years old so the company replaced it! They told me to take the model number and serial number and take it to a Grainger in my area. When I called them; the guy wasn’t nice and said that I needed to show a receipt for the heater which was purchased by my husband who passed away. So I called another company that sold this brand and they replaced it with nothing more than the sticker from the front of the heater. “General Plumbing” – they were wonderful!!

  5. Excellent information. Confirmed beyond a doubt that tank needs to be replaced as it’s leaking from the bottom. Hello 2k expense tomorrow

  6. Cullen on said:

    I have a 19 year old A.O. Smith water heater and have a puddle built up around the base. I have ran the dehumidifier for 2 days and it has not dried up. The insulation around the access panel near the burner is wet so it looks to me like the bottom of the tank is leaking. It was fine until I decided to drain the tank. There was a lot of sediment and sludge that came out of the bottom. After that I noticed the puddle on the floor. The drain is not leaking. Time for a new water heater??? Recommendation on brand? Thanks

    • Water Heater Leaking Info on said:

      Yes, it definitely sounds like you need a new water heater. As far as brands go, always make sure to do your own research before making a purchase. Rheem, GE and Whirlpool usually make pretty good products though.

  7. Kristen on said:

    After being out of town for several days, my husband and I realized this morning that our hot water heater is leaking. We’ve contacted a plumber, but they won’t be able to come out until tomorrow. The floor in the bedroom closest to the water heater is soaked (carpeted floor). What should we do in that room in the meantime while we wait for the plumber??

    • Water Heater Leaking Info on said:

      Follow the directions in the article. The most important thing is to shut off the power and water supply to your water heater. It would also be a good idea to open some windows and run some fans in the area of the leak to dry it out and prevent and mold from growing.

  8. Linda on said:

    Hello and thank you for this site. Two weeks ago I woke up to find part of my living room floor soaking wet and it got worse and worse until 1/2 the carpeting was soaking wet. I called a plumber and he looked at my hot water heater and said it is leaking and shut off the breaker switch but didn’t shut off the cold water supply and things got even worse – the hot water heater is located in a utility closet in the kitchen which is separated from the living room by a wall. The next day a carpet cleaning company began helping me salvage my carpeting using fans and a humidifier and also attached a short hose from the hot water heater valve to flow into the floor drain. The carpetting eventually dried. Two days ago I had my HVAC inspected (to make sure water wasn’t coming from the condensation line) and the repairman turned on all breaker switches – and also briefly removed the hose from the hot water tank – and verified water leaked from the bottom of the tank – now the carpeting on the other side of the utility closet is wet again but the hose was only off about 5 minutes. I know the breaker switch for the hot water heater is on the same row as the HVAC system but can’t tell exactly which one because the legend is confusing and not all switches are marked? What should I do because I can’t afford to replace the hot water heater for another 3-4 weeks?

    • Water Heater Leaking Info on said:

      Sorry to hear about all the problems you’re having with your water heater. Any plumber who doesn’t know that you should turn off the cold water supply obviously isn’t very good plumber and I wouldn’t recommend using them again.

      As far as the breaker switches go, just turn a few on and off until you get the right one. If the cold water supply is still on turn it off. If the leak is serious you may want to consider draining your water heater to make sure no more water leaks out. Good luck.

  9. ZuZ on said:

    Thank you for the amazing write-up. I have a horizontal electric water heater in the kitchen’s dropped ceiling and whenever I turn on the water heater for more than 30 min, water starts to seep from the drain valve. It accumulates and starts dripping from the kitchen ceiling! Any idea why this is happening? Cheers

    • Water Heater Leaking Info on said:

      If you’re sure it;s the drain valve causing the problem read the second half of the article above and refer to the section about leaks from drain valve. There are few tips there that should prove helpful.

      • I wasn’t so sure, so i dug deeper into this, and turned out that the heater I have is an A O Smith MEH 100 and it doesn’t have a drain valve neither a T&P valve, only a Pressure Relieve Valve on the Cold Line In, and that was the one leaking from the nozzle. What do you reckon the problem is?! Thanks in advance

        • Water Heater Leaking Info on said:

          I’m hesitant to give any further advice, as I’m really not familiar with that model. It’s probably best to get a plumber to look at it in person before any further damage is done.

  10. Richard on said:

    Hi, came home to find our water heater of course is leaking probably the tank,its a gas heater can I just turn it off at the shut offs and leave the gas on till morning? Wife needs to take a shower for work in am. The plumber is going to be here at 8 am

  11. Marcus Bernath on said:

    Stupid question but if the heater appears to be leaking from the bottom,will it only leak when being used ie taking a shower or will it leak period??

    • Water Heater Leaking Info on said:

      The tank is always full of water, so it will continually leak, but it will likely leak more when you are running hot water.

  12. Mark on said:

    Noticed a small leak running to the drain in the basement. Determined it was coming from around the threads in the TP valve. Drained the tank to below the TP valve, removed the valve, cleaned and re installed with new teflon tape. The small leak still persists. It doesn’t appear to be from the threads. Is it possible that it could be leaking from the threaded coupling that is welded in the tank? Water heater is 15 years old.

  13. Water Heater Leaking Info on said:

    It’s possible. With a tank that old it’s quite possible the problem could be more serious than a faulty T&P valve. If you’ve already tried fixing the the valve yourself then I would recommend calling a plumber for further inspection. It might be something that can be fixed but it’s quite likely the tank needs to be replaced.

  14. Nikki S on said:

    I have a water heater leak and reading through here I don’t see much discussion on what to do to protect the floor. The plumber came out and said I needed to call a restoration company asap to remove moisture from the subfloor otherwise my hardwoods would be ruined (in other areas of the house from where the leak is) and I’d be dealing with dry out and mold issues. The restoration company said its a min $750.00 to come out but would likely be much higher and I’d have to file a claim with my insurance. To my perception it doesnt look like such a big deal, the leek is in the kitchen with vinyl flooring and it has only been observable for a couple days, am I being hosed? Could I just let it dry up? Its a pier and beam house so air under the house would help dry it quickly now that the water heater has been drained and water cut off. please advise asap thx

    • Nikki S on said:

      *dry rot, not “dry out”. he said letting it air dry would cause dry rot down the road and ultimately compromise the structural integrity of the house. This just feels like scare tactics to help the plumbers buddy’s restoration business but I am now worried.

      • Water Heater Leaking Info on said:

        I do have an article about what to do if your floor gets water damaged. You can find it at http://www.waterheaterleakinginfo.com/water-damage/. Dry rot and mold are real concerns. If you don’t like the quote by the restoration company get another company to take a look, or track down some people who have had similar work done and see what they paid.

  15. Hello. We just noticed a small leak. It is in the cavity below the pilot light…I would guess where air is pulled in. The water builds up then drips out of the opening where the plastic screen goes. It then runs into a floor drain. There is a tiny stream of water running down the edge inside that cavity. The unit is seven years old and is in a basement. Am I looking at fix or replacement?

    • Water Heater Leaking Info on said:

      It sounds like an internal leak, which usually means the water heater needs to be replaced. I would have a professional plumber look at though just to be sure.

  16. James P on said:

    I have a small leak from the top of my water heater where the piping that goes into the tank from the T & P valve piping. It is leaking prior to the T & P valve on the water heater side. Can this be repaired or is it only going to get worse and replacement the option?

    • Water Heater Leaking Info on said:

      I am a little confused by your description of the problem, but it’s possible that it might be repairable. Keep in mind that a leak from the T&P valve can mean there’s too much pressure in the tank, which can be a serious problem. If it’s just a faulty T&P valve though it can probably be fixed. Your best bet is to have a professional plumber assess the problem before moving forward.

  17. Kathy on said:

    we have a gas water heater just a little over 6 years it is leaking around the bottom and no rusty water or corrosion still looks new what could be the problem….sure after the 6 year warranty is out it starts leaking

  18. I just wanted to say thank you for this article. It gave me a lot of information to educate myself, try possible solutions and diagnose the leak, which is really important as I’m an American living in a foreign country and want to be sure I won’t be ripped off when communicating what’s happening (and not in English!).

    In my case, it’s a clear case of the water heater being old (10-12 years), corroded (visible rust, water is sometimes tinted, leak is at bottom) and in need of replacement. Unfortunate, but it cannot be anything else.

    I appreciate the time and effort you put into this site. I run my own website, and I understand it’s a lot of work.

  19. david kollman on said:

    my gas water heater is only 2 years old and is leaking from inside somewhere. a plumber replaced the gas heat control because the pilot would not stay lit. the plastic tube inside was plugged with calcium so he put in the new type with the metal probe so this problem would never happen again. it has been two months and now i am finding water puddling under the tank.

  20. JoAnne S on said:

    I have an electric water heater, it has 2 metal plates on the front where the heating elements go into the tank. Wayer is leaking from the bottom plate. How do I fix it? Thanks.

  21. Travis, you ROCK!!! Thank you SO MUCH for your website! The reason I’m posting this is not to necessarily get an answer from you (which actually would be ok since you’d be confirming my suspicions or giving me some more info) but to also alert others who are interested in this part of your website, “Thoughts”, as to what some other problems can look like and maybe mean. Some things I did, like take 360 pics around the whole water heater to see any other issues or problems, were things I would NOT have even THOUGHT of!!

    I was looking at the different posts and Emil Mian’s post on March 16th 2014 was suspiciously like some of the issues we’re facing.

    We have a Rheem 41v50 purchased in 2003.

    I noticed a little water coming between the tiles, looked around at the washer area (my first big thought), then went farther back to the water heater. BINGO.
    We noticed leaking from a fitting just before the dip tube connection. There was corrosion around that fitting, as well as the same fitting from the anode tube to the hot water outlet, but no leak there…YET.

    There are two other issues that I didn’t think of at the time, but your folks’ posts and your replies gave me some hunches and ideas:
    1. When we noticed the leak from the cold water inlet fitting, we of course turned off the water at the shut off valve on the cold water inlet pipe. It was of course located on that pipe before any other fittings or where it’s connected to the dip tube. (There are a total of 3 fittings between the cold water inlet and the dip tube.) Guess WHAT? It DIDN’T shut off the cold water and the leak keep leaking! This really REALLY bugged me. We had to turn off the water at the house. (and left the hot water on at a faucet, which I think is what you’re supposed to do, yes?) So THAT issue has to be fixed, new water heater or no. At least I can intelligently mention it to the plumber without looking like a dork.
    2. I decided to take some pics front AND back of the unit. Oh, MAN! There are two heat trap nipples on the outside top of the tank, I think that’s what they’re called, right? Around the BACK nipple was rust. I swear it looked alien.

    I have a hunch what you’ll say is ‘NEW ONE’!!!
    So now I’ll use the ‘Buyer’s Guide’ part of your website!!

    PS-this is now 4 am PDT and just waiting for 4 more hours until I can get a plumber.

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