Common Water Heater Problems

A hot water heater is one of the most important appliances in your home but often taken for granted. Unless it’s been turned off for some reason, such as while you’re on vacation, a water heater is used every single day. Like any other appliance, problems can come up.

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Fortunately, tank-type water heaters are fairly simple products. While all their components are important, there are relatively few of them when compared to other appliances. Most fixes can be made on your own without spending a fortune. Though if it’s a problem with the water tank itself, a new water heater is usually the only solution.

Below are some of the most common issues homeowners may experience in regards to water heaters and hot water. To make it easier for you, there are sections for both Electric and Gas water heaters. Troubleshooting a problem is essentially a process of elimination so work your way down the list until you find the issue that most resembles what you are experiencing.

As always, if you are not completely comfortable with making the repairs yourself, please call a professional plumber.

Electric Water Heater Troubleshooting

(Click to jump to GAS water heater problems)

(click to enlarge)

Water Leaking From the Top

If you believe you have a leak near the top of your electric water heater, it could be one of a few things. The cold inlet or hot outlet pipes may be loose, the T&P valve may have failed, or inlet valve may be leaking. All are easily fixed. For more information, see Water Heater Leaking from the Top.

Water Leaking From the Bottom

An electric water heater that’s leaking from the bottom is typically because of normal condensation, a leaking electric heating element gasket, or a small amount of water being expelled through the overflow pipe because the T&P valve is opening to release excess pressure in the tank.

In some cases, the actual tank is leaking and the only fix is to replace the water heater. For more information, see Water Heater Leaking from the Bottom.

No Hot Water

Water in an electric water heater is heated by two heating elements (in most cases). The most common reason for absolutely no hot water is that the circuit breaker has tripped and you should first check the breaker box.

If that’s not the cause then the heating elements may have failed and need replacement. It may also be an issue with the limit/reset switch on the thermostat. It may have tripped due to the water being way too hot or simply failed and needs replacement.

Not Enough Hot Water

Not having enough hot water is most likely due to an issue with the thermostat. It may be as simple as adjusting the desired water temperature on the thermostat for the particular heating element.

On electric models, the thermostat is usually hidden behind an access panel on the side of the tank and a layer of insulation. Unlike gas models, an electric thermostat is set at the factory and not intended to be changed but is sometimes necessary to do so.

During the cold winter months, you may need to slightly raise the thermostat temperature since the hot water gets cooled quicker through colder pipes as it travels through your home’s plumbing.

Other possible reasons for not having enough hot water include a faulty thermostat, faulty element, loose wiring, or simply a water heater tank that’s too small for your needs. See “What size water heater do I need” for more info.

Water is Too Hot

Again, this is likely related to the thermostat(s) where the temperature is set too high. Simply gain access to the thermostat and adjust as needed. This may also be needed when transitioning from cold to warm seasons. For our recommended temperature setting, click here.

If you cannot lower the water temperature low enough, you may need to replace your thermostat or there may be some type of wiring issue (recommended to call a pro if the later).

Water Takes Too Long to Reheat

This is one of the downsides with electric water heaters. On average, recovery time (time it takes to reheat entire supply of water) on an electric model is double that of a comparable gas model. The amount of time it takes to heat up water can vary quite a bit between different models. Newer is usually better.

That said, if it’s taking longer than usual for the hot water to recover, there may be an issue with the heating elements (including sediment build-up on them) or thermostat and those parts may need to be replaced.

If your household tends to use more hot water now than a few years ago, you may want to consider investing in a new model with a larger capacity tank, a tankless model, or installing a point-of-use water heater that’s close to the water source you use the most (ie: the shower). But we recommend to do some research on the tankless vs tank water heater comparison.

Low Hot Water Pressure

Most often, those reporting to have low hot water pressure have an older home with 1/2-inch diameter galvanized piping that enters and leaves the water heater. Since water pressure is automatically limited, the only solution is to install modern 3/4-inch piping which allows more water to flow through.

Sediment, calcium-deposits, and rust inside your plumbing or sink aerators may also contribute to low hot water pressure.

Water Heater is Making Strange Noises

If you hear popping, hissing, banging, knocking, or other strange noises from your water heater, it’s most commonly due to scale build-up on your heating elements or too much sediment build-up in the bottom of the tank.

Other causes of noises include a leak somewhere, too much pressure inside the tank, or noisy pipes because of normal expanding/contracting. When your water heater is making noise, it’s often harmless but should always be looked into for piece of mind.

Dirty or Rusty Colored Water

Rusty hot water is often a sign of corrosion of the anode rod or even tank itself. If left untreated, your water heater will most likely need replacing once the corrosion gets serious enough for the tank to develop a leak. Replacing the anode rod is easy to do and can add years to your water heater.

If the water is not rusty but dirty or discolored, it may be because of scale build-up on the heating elements or sediment that’s making its way into the hot water outlet.

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Smelly Hot Water

Most likely, smelly or stinky hot water is due to bacteria in the tank. Homes which use well water as their water source are more susceptible to their water giving off a foul odor. Periodic flushing of the water heater may temporarily help but to actually fix the sulfur or rotten egg smell from your hot water, you’ll likely need to replace the anode rod. Better yet, consider a powered anode rod which will get rid of the smell and last the longest.

A quick fix may be to increase the thermometer temperature to about 140 degrees to kill off any remaining bacteria.

For more detailed information on troubleshooting an electric water heater, watch the video below:

Gas Water Heater Troubleshooting

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Water Leaking From the Top

Same as with an electric water heater, you should first check the cold water inlet and hot water outlet pipes and connections to make sure they are not loose. A faulty or loose temperature and pressure relief valve or inlet valve may also be the cause of leak.

See Water Heater Leaking from the Top for more information.

Water Leaking From the Bottom

When you see water that appears to be leaking from the bottom of a gas water heater, it could be because of condensation (try turning up the thermostat), a leaking or loose drain valve, or the T&P valve draining some water through the overflow pipe due to tank overpressurization.

If the leak is from the water heater tank due to corrosion, replacement of the water heater is necessary. See Water Heater Leaking from the Bottom for additional information.

No Hot Water

The very first thing to check is if you have gas flow and that your pilot light is on. If yes, the issue may be with the thermocouple which is not correctly sensing that the pilot light is on and in turn does not ignite the gas. The thermocouple may need to be replaced (or simply cleaned).

If you have a newer style water heater with electronic ignition, check your breaker box to see if the circuit breaker is tripped. See here for more info.

Not Enough Hot Water

Some reasons for not having enough hot water or running out of hot water too soon include not having the thermostat set at a high enough temperature (especially in the winter months), a faulty thermostat, or a broken or damaged dip tube which allows the incoming cold water to mix with the hot water at the top.

Sometimes not enough hot water is simply because you have a water heater tank that’s too small for your needs. Even though you may have a 40 gallon tank, only about 28-30 gallons of it may be usable hot water at a time. Upgrading to a larger water heater or a tankless model may be in your future.

Water is Too Hot

Most likely, you have the thermostat set too high. This is most common when transitioning to the warmer Spring and Summer months and forgetting to set back the temperature after raising it to account for the colder Winter temps. Less likely is a faulty thermostat that needs replacement.

Water Takes Too Long to Reheat

If it feels like your gas water heater recovers too slowly, the thermostat may be set too low, the burner orifice may be too dirty or clogged and requires cleaning, the gas pressure may be too low, or the vent flue may be too dirty and also require cleaning.

For many, it’s simply a matter of having too small of a water heater tank for their family’s needs and it’s never given a chance to fully recover.

Low Hot Water Pressure

If you have an older home, there’s a good chance you have the smaller 1/2-inch diameter galvanized piping throughout your home. This greatly reduces the amount of hot water than can flow through your home’s plumbing.

Unfortunately, the only way to get noticeably higher hot water pressure is to switch out to the newer 3/4-inch piping that’s used in today’s homes. Definitely not a small task.

You may be able to slightly increase water pressure by cleaning out sink aerators or shower heads which tend to get clogged over time. Also, make sure your water inlet valve is fully open and not partially closed.

Pilot Will Not Light

When you know exactly how to light a pilot light on a water heater yet it won’t light, there are a few possibilities as to why. Either the pilot light orifice or tube is clogged or needs replacement, the thermocouple is loose or faulty, there is air in the gas line, or the gas valve is defective.

Pilot Will Not Stay Lit

Just as annoying as a pilot light that won’t light, is a pilot light that frequently goes out. Often, thermocouple replacement is necessary but there are other reasons if your pilot light keeps going out. Other possibilities include a bad gas valve or partially clogged vent which can cause downdrafts that blow out the pilot light.

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Burner Does Not Stay Lit

A burner that at times goes out or produces an unusual, higher or lower than usual flame or even a whistling sound, is most often due to dirty or clogged burner orifices. As with the pilot light, a faulty thermocouple or dirty vent may also be the cause of the problem.

Water Heater is Making Strange Noises

Same as an electric water heater, hissing, popping, knocking, or banging noises can sometimes come up. On gas models, this is typically due to sediment build up in bottom of the tank, expanding/contracting piping which rubs against wood framing within the walls, or dirty/clogged parts which gas flows through.

Rusty Colored Water

Once again, corrosion of the anode rod or the inside of the water tank itself is usually to blame. While replacing the anode rod isn’t complicated or expensive, the bigger problem lies if the tank shows signs of corrosion. It’s then only a matter of time before a leak develops and a new water heater will be needed.

Smelly Hot Water

Likely due to bacteria build up inside the tank. Simply turning up the thermostat to about 140 degrees should kill off the bacteria but a full clean-out of the tank with chlorine bleach may be necessary. If the smell comes back, the anode rod is likely at its end of life and will need replacing.

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  1. Hello, I have a Jacuzzi tub in an upstairs bathroom far from the hot water heater. I am going to run 3/4″ PEX tubing from a tee in the hot water line in the basement up to an auxilliary hot water heater in the bathroom where the Jacuzzi is. I only have enough room for a 4 gallon heater with a 1/2″ inlet and outlet. Will I have enough volume and/or pressure to fill the tub?
    It previously had 3/4″ copper up to the bathroom and then 1/2″ going to tub. The second heater will be inline with the main water heater, so do you think the 4 gallon tank will help to fill the tub with hot water? The main by itself does not.
    Thank you for any advise you can give me.

  2. I have a gas water heater, the gas supply line is so hot that it is melting the protective foam cover. Any suggestions as to what it might be?

  3. Great article! Homeowners can empower themselves to troubleshoot before calling their local plumber. We repair hot water heaters quite often in our area and the majority of the time it is due to a lack of maintenance. The best thing a homeowner can do to ensure high performance and long lasting heating from their tank is to have it flushed annually. This will prevent sediment build up, odor, bad tasting water, ect. It greatly improves the quality of your water heater and can prevent many of the issues stated in this article. Which was a great article btw, it outlines what homeowners can due to troubleshoot before calling their local plumber.

  4. Hi my ignitor comes on in my gas hot water tank but will not lite burner what may cause this as I thing maybe a new ignitor will fix this as maybe not drawing enough current please share your thoughts on this

    • With the gas off, are you seeing a spark when you press the igniter? If so, have you tried cleaning the pilot line? A clogged line or dirt/deposits around the burner are often the culprit. If no spark, first check your wire connection but a new igniter may be needed.

  5. after replacing gas hot water tank i now have large amounts of air build at my faucet nerves a problem before installing new tank. appreciate your response

  6. I was gone for a month so no water was being used. Now that I’m back, I have about 5 minutes of hot water before it goes cold. Anyone know why that could be?

  7. Hi I have the electronic automatic water heater. When I plug into Electricity connection,the total power has shutdown.Tried with another plug port. But I am getting the same problem. Can you tell what I have to do ?

  8. My gas water heater is making a rushing noise several times a day. We have added a larger over flow tank and replaced the pressure valves. This stopped the rushing noise for about 4 months but now is back. This is a new house built 2 years ago. Any suggestions?

  9. hi my heater has been making clanking sounds while is on and its also leaking black water that smells like something has burned. my landlord has had multiple plumbers come in to “fix” it but its getting worse. any suggestions on what to do????????

  10. I have a 40 gallon gas unit that does not get hot enough. No matter where I turn the thermostat setting, it only gets lukewarm water to come out. The pilot light is lit and I’ve see the burner come on (once) but the water never gets hot before the burner cuts off again.

  11. My State Select 50 gal. gas water heater will not maintain the temperature. When we don’t use it for a long period the water is just a little warm. If we run the water for a while it kicks in and heats up.

  12. My old hot water heater and second brand new heater are not working, because the cold water continues to run in heater or backing up even when heater is full. No one knows what’s wrong. Could it be busted pipes, and our meter shows no signs of leaks.??????? Where is the water going, I can’t get hot water at all

  13. I have replaced both heating elements, and both thermostats. I have the thermostats both set on 150*. I am only getting luke warm water at the faucets, though if I discharge water out of the top relief valve, steaming, very hot water is present. I’m pretty much in the same situation I was before the replacements of said parts. Can anyone help shed some light on my problem?

  14. I have a 6-7 yr old Whirlpool 50g gas water heater. Recently the pressure relief valve has been releasing pressure on a regular bases. I have lowered the temperature setting and it still does it. I have hard water and know there is a lot of sediment build up in the bottom of tank. Could this be the reason or is it more along the lines of the valve itself? Or possibly the temperature probe?


  15. My gas water heater is gushing water from somewhere underneath when I turn the water . Went to empty the tank and was already empty. Top and sides of tank dry. Tank only 6 months old and started gushing in middle of night. Help please

  16. My hot water heater is side hub and has water coming out of both while hooked up so I have shut off the power and water to it, now I’m trying to find out why it might be doing this and what I can do to fix it, can anyone give me a clue on what might be the problem. I think it might be settlement but I’m not 100% sure so I’m trying to check all avenues.

  17. I have a propane gas water heater 50 gallon, the water is cold, we tried to relight the pilot but it failed, we tried three times, is it easy to remove the gas valve and install new one or do we need a plumber to repair that gas valve or may be the gas line to the burner, everything is sealed or is better to replace the water heater, it is around 8-9 years old, a Kenmore model.

    • Replacing a gas control valve is definitely doable if you take it slow. The problem is that it’s a fairly expensive part and for a 9 year old water heater, a new water heater might be worth considering. If you’ve ruled out the thermocouple being the issue, I’d recommend getting a free quote in your area on a gas control valve replacement just to see where you stand.

    • You already replaced the thermostat and the water is still too hot at the lowest setting? Keep in mind that water heaters with two heating elements have two thermostats. It’s possible there’s a short in a heating element as well which keeps it on all the time.

  18. My gas water heater is making a rushing noise, leaking water from the back, bottom side,and also one of the pipes feeding into the tank gets hot when I turn the water back on. It’s been off all day, along with the pilot and the hot water heater itself.

  19. I had a new water heater installed. The T&P and drain valves feel very, very hot. The top of the discharge pipe near the T&P valve is also very hot. Is that normal?

    • You likely have a closed loop system with no expansion tank installed. In that case, the valve is doing its job and probably releasing a bit of excess pressure in the tank. I’d recommend putting in an expansion tank.

  20. I have a electric hot water heater upstairs and gas downstairs. Both went out at the same time. I have checked the breakers. The gas is also leaking somewhere on the top. I see water running down, but do not see from where it is coming. Any ideas?

    • If gas is leaking, the water heaters not working should be the least of your worries. If you smell a rotten egg smell, it’s possible it’s only a chemical reaction in the water but to be sure, I’d call a plumber asap!

  21. I have a gas water heater that is 4 years old. I typically never have any issues except for this morning. After taking my usual 15 minute shower I went to get dressed and heard what seemed to be air escaping from the water heater. I turned the water heater off for a minute or so then turned it back on. The noise has stopped and I’m keeping an eye on it. This is a 50 gallon heater. Any thoughts?

    • There might be air escaping through the TPR (temperature pressure relief) valve if the valve is faulty but you shouldn’t really have an issue with excess tank pressure after a 15 minute shower. Try turning down the water heater thermostat a bit the night before your shower and see if that fixes the issue.

      The noise could also be due to when cold water which enters the tank to refill it makes contact with hot parts inside the tank and makes more of a hissing noise. Condensation on the outside of the tank could also cause the noise.

  22. Old water heater working but was leaking, replaced with new (both electric, same size). All working fine. Five days later, no hot water. Ideas?

    • Check to make sure your breaker didn’t trip. If so, simply reset. If it happens again there’s probably a wiring issue.
      While rare for a new water heater, it’s possible a heating element failed. Just like with other appliances, there is occasionally a manufacturer’s defect on a part. Contact whoever installed it or contact the manufacturer if it was a DIY install.

  23. Our brand new gas water heater makes a bell like humming noise. The tank itself is making the noise. This usually happens in the morning when the kitchen faucet is turned on.

  24. For years I have had a problem with my electric water tank. Every time I run a bath (or fill the sink etc) the hot water runs for a few minutes and then slows to a trickle and stops. I runs long enough to fill 2 to inches in the bath and then stops. I turn the tap off then leave it for about 5/10 minutes and then I run the water again, and again it runs for a few more minutes and slows to a trickles so I repeat until I get enough water fro a decent bath. I’ve put up with this for about 15 years now (I live on the 9 floor and once many, many years ago I flooded my neighbours downstairs so this problem has been my insurance against repeating that!) I’ve meant to sort it for years but never get round to it, any ideas what it might be? A faulty ballcock arrangement, a blocked or dodgy gate valve, low pressure (I’m pretty sure its not the pressure as the cold water runs good)?

    • Interesting. This does it on all hot water outlets? What happens if you let the hot water flow stop for the tub and then open a hot water faucet in a different part of the apartment?
      I would lean towards there being some kind of check valve issue at the top of the water heater. Alternatively, the wrong type of washer could be installed at the faucet. If the wrong material is used, the hot water could cause the washer/gasket to expand and stop water flow. Also, make sure any hot water shut off valves are fully open. The inside could also be affected by heat and shut off water flow if they’re not fully open.

  25. We were gone for 6 months, shut off the electric water heater while we were away. When we returned, our hot water supply is not as hot as before and runs out after 5 minutes. What should we check?

    • Unfortunately no since you first have to push out the water that’s currently in the water pipes. Although you can install a point of use water heater directly under the sink you’re using so you’re not wasting water. It just wouldn’t make sense to do that at every faucet in the house.

  26. We just moved into a house with a 4 year old natural gas water heater. For the 5 months we’ve been here, everything has been fine. The last couple of days though we’ve noticed the water is not as hot as it used to be. From what I can tell, it seems to be related to our routine of water usage in the house. If the water in the tank has been sitting for a while, it is acceptably hot enough for me to shower, but my wife complains that it’s too cold. In this instance, if I hold my finger under the water, it’s hot but not enough to burn me or make me move my finger. I’ve noticed that once the heater drains and refills and heats back up, that freshly heated water is considerably hotter to the point that I can’t hold my finger under the faucet for more than a couple of seconds. Thinking back over the past few months about our daily routine, I’ve been waking before my wife, showering, and then she showers after me and everything is ok. Yesterday though I was home sick from work and she showered before me and complained about the water being cooler than usual but that quote “it’s probably hot enough for you to use it.” Tonight, she tried to use our jetted tub and the tub filled with just kind of hot water. I immediately held my finger under the running tap to test it and it was just kind of hot but I could keep my finger there without a problem. After about 10 minutes I tried this test again and the water was extremely hot to where I could only hold it under the faucet for a couple of seconds again. Any idea why older standing water in the tank is much cooler than freshly heated water in the tank? And how can we fix this moving forward? Our thermostat on the unit is set to the letter “B.” Next is setting “C” and then “Very Hot.” Unfortunately I don’t have a thermometer handy to measure the temperature. Thanks in advance for your help.

    • This is a bit strange if we’re talking about a gas, tank-style unit. If you consider how one works (dip tube sends cold water to bottom of tank, the flame heats it up, and hot water exists from the top of the tank) this obviously shouldn’t be happening (warm water changes to hot after a few minutes). Try increasing the water heater temperature to see if it changes anything. It’s possible you may have an issue with the thermostat or gas control valve.

  27. We have an electric water heater that is 12 yrs old. When taking a shower or bath we get lukewarm water. After about an hour we try again and get hot water. Any suggestions?

  28. Have a problem my cold supply line is hot both line are hook up right the problem that I’m seeing is that both supply line have come together about too feet from the top of tank

  29. Help please…since November having problems with furnace firing frequently with minimal to no water use..4 minutes or so it runs..we do not have problems with water temp or running out of hot water except at end of baths. We have 3 people in house..fired about very 2 hours regularly in 24 hour period.furnace people have replaced control panel on thermostat on Amtrol longer period it fires..went 5 hours yesterday..but then cycled twice in 20 minutes after a short shower.I have had 2 different companies out here that can’t figure it out..multiple service calls with still same problem..any ideas and help appreciated.

  30. My gas hot water tank kicks out when it trying to heat. It just keeps clicking. I unplug for say 20 min then it will fire again but not stay going.

  31. I have a newer John wood yet it takes 10 ish minutes to get hot water to my kitchen (approx 30ft) and bathroom (50ft) of travel distance from tank would anyone have ideas of where I should start troubleshooting this?

  32. The water in our rental unit runs hot for about five minutes and then goes cold for a little while then it heats up again. Any suggestions? The tank is electric!

  33. I am glad that you brought up not having enough hot water could be caused by a number of things like the thermostat, wiring, or a small tank. My wife and I just bought a small apartment and it seems like the hot water lasts for all of two minutes. Which isn’t long enough for a decent shower, even with both of us in it. We will have to contact the facility and see when they can get a plumber to see what is for sure wrong.

  34. How does one keep the perforated grate clean on bottom of 50 gal. LP water heater. The grate allows air to enter heat chamber but gets clogged. I can brush the grate and it resolves the situation for awhile, sometimes a day or two, sometimes weeks. I can light the pilot after brushing grate but stoppage reoccurs.

  35. I have a gas water heater. My bathroom is on the other side of the house and has hot water but my kitchen which is right behind the water tank no longer gets hot water.

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