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Common Water Heater Problems (Causes & Fix Methods)

Modern water heaters are built to last. Many come with long warranties, and you hope to be able to use them trouble-free for many years to come. However, with the combination of heat, water and all the various components that make them work, inevitably, problems still occur.

Many issues are not fatal for your heater, and the key to repairing them is correctly identifying what’s wrong. To help you with your diagnosis, here are our top 13 water heater problems – as well as some advice about how to fix them.

Common Water Heater Problems – Before you start

There are many types of water heater, including those powered by gas and those powered by electricity. Electric water heaters are high-voltage appliances, which means you should take full precautions when working with one.

Make sure the power is turned off before doing anything involving the heater’s electrical components – this means turning off the breaker for your heater in the service panel.

Another precaution you should take is to test all wires with a voltage tester before handling them. Failure to do so can result in a serious injury or even death.

1. Water Heater No hot water

No hot water

If you have no hot water, there are several possible reasons, and you need to work through each of them methodically to eliminate each one – and this will also depend on whether you have an electric or gas-powered heater.

The most obvious reason an electric heater doesn’t work is that it’s not receiving any power.

Start by checking the circuit breaker to see if it has been tripped. If it has, it’s an easy fix – simply turn it off and turn it back on again. You may also have to replace the fuse if it has blown.

The next step is to check the high-temperature cut-off. Open the panel and press the red “reset” button. Check to see if the water will now heat.

Another possibility is that you have a faulty heating element or elements. Test these and replace as necessary.

After checking each of these, if you still can’t find the reason why you have no hot water, it might be time to call a professional.

If you have a gas heater, check to see if the gas valve is open. If this is not the problem, you may have issues with the pilot or the burner. Check #10, #11 and #12 below to see how to address these issues.

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

2.  Water Heater Not enough hot water or water not hot enough

Again, if you don’t have enough hot water, the reason why will depend on the type of heater you have.

If you have a heater with a tank, it may simply be that your tank is not big enough for your requirements. If your tank is too small for the number of people showering, for example, you may use up all the hot water before everyone is finished.

If this is the case, you need to think about buying a new water heater that can meet your needs.

If your heater produced enough hot water for everyone before but suddenly stopped or no longer heats the water enough, the problem is probably due to a heating element failing. Check them and replace as necessary.

Another quick fix is to check the thermostat – you may just need to turn it up to a higher setting. Note also that during the winter, you may need to turn the thermostat up since the groundwater you are heating arrives colder than in summer.

If you have a tankless heater, you may be trying to run too many fixtures for the unit’s power, so check how many fixtures your unit is rated for. The problem could be that your heater is not powerful enough for your requirements.

Tankless heaters also have to work harder in winter, so if you experience this problem during the colder months, this could be the reason. You may need to consider upgrading to a more powerful unit.

3. Water too hot

Water too hot

This is almost certainly due to the thermostat being set too high, but it’s an easy problem to resolve. Simply turn down the thermostat and you should be good to go.

If this doesn’t do the trick, check the temperature pressure valve – if it is faulty, the heater won’t shut off when it reaches the correct temperature. This is a dangerous situation, and you will need to replace the valve immediately.

4. Water Heater takes too long to heat

Water takes too long to heat

Possible reasons for water taking a long time to heat include faulty heating elements, sediment build-up on the elements and a faulty thermostat. Check each of these in turn and replace as necessary.

If you have a gas version, it could be related to the burner – see #12 below for further information.

5. Low water pressure in Water Heater

Low water pressure is often caused by not having wide enough pipes. Older homes mostly have ½” pipes while modern homes usually use ¾” pipes.

If you live in an older home and you are suffering from low water pressure, the problem may not lie with the boiler at all – you may need to consider fitting wider pipes in your home to resolve this issue.

6. Leaks in Water Heater

Leaks

Leaks might result from loose connections, in which case you will need to tighten them with a wrench. They can also come from valves, and these can be replaced.

If the leak comes from the tank, this is more serious since it may be corroded. If you have a corroded tank, it will need to be replaced entirely.

7. Dirty water in Water Heater

Dirty water

If your water starts to turn to a dirty rust color, you are probably looking at corrosion inside your tank. The only solution for this is replacing the tank.

However, it could also be due to a failing anode rod, so before replacing the tank, flush the tank and replace the anode rod to see if this fixes the problem.

8. Smelly water in Water Heater

Smelly water

If your water smells bad, bacteria in your heater could be the culprit. This is especially common if your water comes from a well. Flushing your tank can help, or you can try boiling the water to maximum temperature to kill all the bacteria.

If this doesn’t work, try cleaning it out with chlorine bleach.

If you have water that smells of rotten eggs, it could be due to a failing anode rod – in which case, you should replace it.

9. Water Heater Tank makes noises

Tank makes noises

There are a few reasons water heaters may make noises. The most common is that a build-up of scale in the tank and on the heating elements is creating rumbling, popping and banging sounds as the water heats.

If this is the case, try draining the tank and descaling. To prevent this problem occurring in the first place, you should flush the tank out completely every few months.

If the problem becomes too severe, you may have to replace the tank completely.

Sometimes water heaters and pipes can make sounds through normal expansion and contraction due to heat. This is harmless, but there’s not so much you can do about the noise.

10. Water Heater Pilot doesn’t light

Pilot doesn’t light

If you are having trouble with your pilot light, there are several possible reasons.

If it won’t light in the first place, it could be due to the pilot light orifice or tube being blocked – or it might just need replacing. Another possibility is that the thermocouple is loose or faulty. You could also have air in the gas line, or the gas valve could be faulty.

11. Water Heater Pilot lights and then goes out

If it lights but then goes out, the causes could be similar. The thermocouple could need replacing, you could have a bad gas valve, or the vent could have become blocked.

12. Water Heater Burner goes out

Burner goes out

This is likely to be a similar issue to problems with the pilot light. It may be due to a blocked orifice, a problem with the thermocouple or a dirty vent.

13. No hot water for bathtub

No hot water for bathtub

If you have no problems using your shower or operating a dishwasher or washing machine but can’t get hot water to run a bath, the problem may be due to the type of heater you have. If you have a tankless heater, this is probably the root cause.

Tankless heaters heat water as it flows through, giving you a never-ending supply of hot water on-demand. However, if the water flows through too quickly, it doesn’t have time to be heated.

Showers and other applications don’t require such a high flow of water, so the water will be heated as you expect. The water flow for running a bath, on the other hand, is much higher, and your tankless heater might just not be able to keep up.

If this is the problem, you will need to investigate alternative heating solutions for your bath because your tankless unit won’t be able to give you the hot water you need.

Identify the problem early

Often, the most important thing you can do is to identify the problem early and take steps to rectify it. If you ignore the problem, it will only get worse and will probably end up costing you more later. And with this guide, now you have a good idea of where to start looking.

21 thoughts on “Common Water Heater Problems (Causes & Fix Methods)”

  1. Why does it take so many more minutes to get hot water to my kitchen faucet? I have a tankless gas water tank. Is there any way to remedy? I feel like I am wasting tons of water

    • I had a Bosch Tankless Gas Fired Water Heater many years ago, and found that there is a small tank within the unit that does mix cold and hot water. It does need an Annual-to Bi-Annual cleaning with a special chemical to get rid of sediment and clean the mixing tank. This may be the cause of the wait time or if its a digital model, I would have a professional ascertain whether or not the the unit is properly calibrated.

      Hope this helps.

  2. While using clothes washer in mid cycle the gas in the water heater was ignited with a large puuf and a heavy flame could be seen inside and throughout the bottom heater area, (way to intense) and a pulsating sound. What happened?

    • Sounds like the burner assembly needs cleaning. Also check to make sure the pilot assembly is burning blue flame… It may also need cleaning. The pilot assembly needs to supply flame close enough to the burner for proper ignition. Most of the time cleaning the pilot orifice will allow a better flame for ignition.

  3. It’s the distance the water has to travel. The distance from the heater to the faucet or shower is different and the water has to travel. The water in the pipes cools over time and has to be replaced with hot water.. No way to remedy. It is what it is.

  4. my water heater has hot water some days and warm water other days .what should i look for thanks

  5. I changed both heating elements out in my electric hot water heater today and within an hour had hot water and did a load of laundry. Then sat down to eat dinner and watch a movie. Afterwards water was ice cold again. I opened the top panel and pushed the “reset” button. It clicked letting me know the power had been shut off for some reason. I need to know what causes this and how to fix it. Do I need to replace the thermostats??

  6. Hi my name is Barbara and we bought a prowler travel trailer a few months back. we have a problem with the hot water. So sometimes we will get lucky and the hot water will come on for a few hours but most of the time no pretty much all the time we have no hot water. I can hear when the pilot lights but it wont stay on

  7. I live in Hawaii in a post and Pier House. I am on a catchment water system. So my pipes are under the house and underground. During the summer months when I turn the cold water faucet on scalding hot water comes out and it takes a long time running before the water turns cold. I’ve had the water heater flushed and the anode rod changed in September of 2020. That plumber told me the hot water is backing back into my water heater because I don’t use enough hot water. How do I fix this problem?

  8. my water heater was installed last February and I notice the water is black and smells. I had a bath tub that we don’t hardly use and when I turn turn on the hot water it come out black .

  9. Why do I need to tap on my Honeywell gas control valve to get burner to lite?

  10. Have elect wh. changed lower element and cleaned out scale in tank. will not go on. changed upper control. still no Hot water. tested controllers, on top shows 240 and 120 when grounding tester. upper element shows 240 when tested but will not heat. lower element shows 120 when grounded on all contacts. when testing both contacts (lower)on element shows nothing, no reading.

  11. After a hard freeze in Texas my electric water heater stopped working. Now months later the water is hot again. Should I be concerned?

  12. power vented 40 gallon cellar flooded heater starts gets flame and then shuts down

  13. I have the same problem as Jack Corona. Hot water some days warm other days. I have 2 50gal tanks as well. The water has started hot but after a few minutes in the shower its warm.

  14. We have to turn the faucet in the shower almost all the way over for the water to be hot enough. The temp on the electric water heater (14 years old) is on 140 and just changed it to 160 . Is there anything we can do to remedy this situation or is it a sigh the heater is going bad?

  15. Thank you for pointing out that if you have a tankless heater, you may be trying to run too many fixtures for the unit’s power, so check how many fixtures your unit is rated for. Our heater in the house is no longer working. Thanks for giving us an idea of our options of where to find water heater repair.

  16. the pipe fitting came loose on top above the water hesater its electric, water dripped slowly onto the wired on front we heard a popping sound and went to check it out and there were sparks coming from the wiring harness then no hot water we changed wired with a different water heater still no hot water.. what can we do or what could be the problem

    • ?

  17. Here’s one that you can add to the list.A.G.Smith heater. Water heater is about 5 yes old. I do have expansion tank. Problem: Safely popoff leaking sporadically onto concrete garage floor.
    Here is what I have done thus far.
    1. New safety value, exact replacement part.
    2. New High and low thermostats. Likewise specified as exact replacement for this heater.
    3. Confirmed heat elements are ok.
    4. Drained heater and flushed out all sediment.
    5. Turned on water and bled tank and lines to remove all air.

    Whan next? I’m out of ideas. We have been here since 2006 and only recently did this start.

  18. My upstairs bathrooms (master & guest) adjacent to each other were not suppling hot water.
    Then no cold water (this was in both locations). When they started working there was sentiment with the water.
    I had a plumber come out and replace a cartridge behind each bath unit and that seemed to resolve the problem.

    Then the problem reoccurred. Is this a water heater problem or a pipe issue?

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