What to Do if Your Water Heater Is Not Working Properly

If you’re expecting hot water and it’s cold instead, there’s a good chance that your water heater is not working like it’s supposed to. While there are multiple issues that could cause your water heater to stop functioning properly, many times you can diagnose and fix the problem on your own. Keep reading for advice from professional plumber Rob Calame on common causes and fixes for your water heater and how to keep it maintained . Just be sure to follow safety precautions before you start any repairs.

What to Do if Your Water Heater Isn’t Working

Check the breaker in your electrical box, and turn it on if it’s been tripped.
Relight the pilot light on a gas water heater if it’s gone out.
Inspect the water heater for leaks and ensure the water and gas supplies are turned on.
Push the reset button on the water heater thermostats, or replace them if they’re faulty.
Flush your water heater to remove sediment and mineral buildup.
Replace any broken or corroded dip tubes or anode rods inside the tank.

Section 1 of 5:

Causes & Fixes for a Hot Water Heater Not Working

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1
Tripped breaker If there’s a power surge or if your water heater draws too much power, then it may trip the breaker. When the breaker goes off, it cuts power to the unit and it won’t be able to heat your water properly. For gas water heaters, a tripped breaker can prevent the pilot light from lighting.
- How to Diagnose: Calame says, “If it is an electric water heater, I would check the breaker and make sure that the breaker isn't still tripped.”
- How to Fix: Flip the breaker back into the On position. Calame also mentions that if there’s a deadman switch or on-off switch on the power source, turn it on as well.
2
Unlit pilot light The pilot light is a flame that ignites the burner on a gas water heater when the water gets too cold. If the light ever goes out, then your water heater will not turn on or heat the water properly. ^{[1]
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- How to Diagnose: Remove the bottom panel from the side of your water heater to expose the burner or the viewing glass. If you do not see a flame, then the pilot light has gone out.
- How to Fix: Calame explains “to follow the instructions that are labeled right there on the water heater” because they can vary. To light your water heater , follow these steps:
  - Turn the pilot light knob, push it in, and hold in position.
  - Hit the spark igniter a few times, which is usually a button on the gas intake.push that ignites the spark igniter on the inside of the water heater.
  - Release the knob when the indicator light starts blinking green. You should see the pilot light’s flame from the small glass viewing window if everything is working properly.
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3
Water leak Water can leak out from the supply lines, valves, or directly from the tank. When the unit loses water, then your fixtures may have weak or not flow when you try using hot water. ^{[2]
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- How to Diagnose: Check around the base of your water heater for puddling water and inspect all the pipes and valves for drips. Be sure to check the supply lines, drain valves, and bottom of the tank.
- How to Fix: Start by turning off the water supply valve going into your tank. If the leak is happening on one of the supply lines on top of your water heater, then unscrew the lines from the tank and attach new lines . If the leak is coming from the bottom of the tank, then check and replace the drain valve. If your tank is old, then it may be rusted and you may be better off replacing the unit. ^{[3]
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4
Closed or broken gas valves If you have a gas water heater or a tankless water heater that uses gas, then it has to burn natural gas in order to heat the water inside. If the there isn’t enough gas getting into your water heater, then the water in the tank will stay cold. ^{[4]
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- How to Diagnose: Check the gas intake pipe, and turn the valve so it’s parallel to the pipe to make sure it’s on. Try lighting the pilot light, and if it continues to go out, then there’s an issue with the gas supply.
- How to Fix: If you notice a rotten egg or natural gas smell near your water heater, turn off the power and contact your gas company to tell them there’s a leak. No matter the repair, have a professional utility person replace any gas valves or lines that are damaged.
5
Defective heating elements On an electric water heater, the 2 heating elements near the middle and bottom of the unit. If either of the heating elements are not working correctly, then the water inside of the tank won’t heat properly and it may be cold. ^{[5]
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- How to Diagnose: Disconnect power from your water heater and remove the panels on the side of the tank covering the heating elements. Unscrew the elements and pull them out of the tank. Hold the probes of a multimeter against the connections to test for continuity . If the reading is anything other than 0, then the heating element is faulty.
- How to Fix: Remove the faulty heating elements, and slide replacements into their place.
6
Faulty thermostat Electric water heaters have thermostats on each heating element that detect the water temperature and warm it up if it’s too cold. If the connection is broken on the thermostats, then the heating elements may not turn on and the water will stay cold inside of the tank. ^{[6]
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- How to Diagnose: Start by removing the panels over the heating elements and pressing the reset button on the thermostat to see if it fixes your water heater. If not, set a multimeter to the lowest ohms setting. Disconnect the wires on the thermostat’s screws, and press the multimeter probes against the screwheads. If the reading is anything other than 0, then the thermostat is faulty.
- How to Fix: Unscrew the thermostat from your water heater and pull it out to remove it. Install a new thermostat in its place and reconnect the wires. ^{[7]
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Broken dip tube The dip tube runs vertically through your water heater and brings cold water closer to the heating elements at the bottom of the tank. If the dip tube is damaged or corroded, then cold water may leak into the top of the tank and drop the temperature. ^{[8]
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- How to Diagnose: Turn off the cold water supply to your water heater, and disconnect the dip tube. Unscrew the dip tube and pull it out to check for damage.
- How to Fix: Remove the old dip tube from your water heater and install a new one in its place.
8
Mineral or sediment buildup Water going into the tank of your water heater has small minerals and deposits. Over time, these deposits can build up on the heating elements inside the tank and make them work less efficiently. ^{[9]
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- How to Diagnose: Turn hot water on from one of your fixtures, and if it looks cloudy, then there’s buildup in your water heater. Many tankless water heaters have notification systems to alert you if there is buildup or a clog.
- How to Fix: Flush your water heater . Attach a hose to the bottom drain valve, and place the other end in a drain. Turn off the power and water supply to the heater. Release the pressure valve at the top of the water heater. Then, open the drain valve and let all the water flow out.
9
Too many fixtures using water Every water heater has a limited capacity, and tankless water heaters can only support a certain number of gallons per minute. If you’re using hot water in multiple fixtures or appliances, then the heater might not be able to keep up and water can start feeling cold. ^{[10]
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- How to Diagnose: Check the flow rate or capacity on your water heater, and look around your home for fixtures that are using hot water at the same time.
- How to Fix: Run fewer fixtures at a time. Alternatively, replace your water heater with one that has a larger capacity or flow rate.
10
Frozen pipes When the temperatures dip too cold, the water inside the supply lines leading to your heater can freeze up and prevent anything from flowing. This is especially an issue with tankless water heaters because they only heat water as it passes through the system. ^{[11]
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- How to Diagnose: Check the water supply pipes going into your water heater to see if they feel cold or are exposed to temperatures below 32 °F (0 °C).
- How to Fix: Insulate your pipes to keep them warm and prevent them from freezing.
11
Malfunctioning temperature pressure valve The temperature pressure valve releases pressure from inside the tank so it doesn’t burst when the water heats up. If the valve has buildup inside or fails to open, then your water heater may stop working so it doesn’t get damaged further ^{[12]
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- How to Diagnose: Inspect the valve on top of your water heater for any leaks or damage.
- How to Fix: Drain the water from the top of your tank and unscrew the pressure valve from your tank. Install a new pressure relief valve and tighten it in place. ^{[13]
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12
Old anode rod The anode rod is a long metal piece inside your water heater that’s made to rust and wear away to prevent the tank from corroding. When the anode rod is completely rusted or worn down, the water may damage the tank and prevent your water heater from working properly. ^{[14]
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- How to Diagnose: With your water heater turned off, locate the six-sided screw on top of your water heater and loosen it with a wrench. Carefully pull the anode rod straight out of the water heater and check it for corrosion.
- How to Fix: Pull out the old anode rod, and install a replacement in its place. Tighten the screw to the top of your water heater so it’s completely sealed.
13
Old age Hot water heaters usually last around 10-15 years, but it can vary on how well you’ve maintained the unit. When a water heater gets too old, the parts may start failing and prevent them from heating properly. ^{[15]
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- How to Diagnose: Check the manufacturer label on the side of your water heater for an installation date. If it’s been over 10-15 years, then it’s probably time to replace them.
- How to Fix: Have a professional plumber replace your water heater with a newer model.
EXPERT TIP

Rob Calame
Training Manager at Barnett Plumbing & Water Heaters
Rob Calame is a Training Manager at Barnett Plumbing & Water Heaters, based in Livermore, California, and the Lead Instructor of their Water Heater Training Program. Founded in 2005, Barnett Plumbing & Water Heaters specializes in servicing and installing all water heater types including tank, tankless, and heat pump water heaters throughout the Bay Area.

Rob Calame
Training Manager at Barnett Plumbing & Water Heaters

Opt for a heat pump water heater if you need to replace your old one. There's a lot of hesitancy to switch to an electric water heater, but they have longer lasting tanks and come with longer warranties. They also use little electricity, so they're greener and save customers money on their monthly energy bills.

Section 2 of 5:

Other Common Water Heater Issues

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1
Hot water has a foul odor If you notice that hot water from your faucet has a rotten egg or sulfur odor, it may be caused by mineral deposits that have built up inside the water heater tank. This commonly happens if the anode rod has a lot of corrosion or is broken down. Simply replace the anode rod with a new one to help treat the smell. ^{[16]
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- Odors are more common if your home uses well water, and they will be noticeable whether you use hot or cold water.
2
Hot water tank makes a loud noise If your water heater is making a rumbling or growling sound, it’s normally caused by sediment buildup on the bottom of the tank. If you’re hearing a hissing noise, it may be caused by a leak or condensation on a heating element. ^{[17]
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- Flushing your water heater can help remove sediment and buildup that are causing loud noises.
- If you notice condensation building up on heating elements, make sure that there is a layer of insulation over them to keep cold air out.
3
Rust-colored water If you notice hot water has a darker color than usual, it may be caused by sediments and minerals, or it may be a sign that your anode rod has corroded. Flushing your water heater of the residue and replacing your anode rod will do the trick to make your water look clear and clean again. ^{[18]
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- You may need to flush your water heater multiple times to completely drain out the debris and discolored water.

Section 3 of 5:

Preventing Issues with Regular Maintenance

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1
Flush your water heater to clear out sediment. Calame agrees that you must flush your water heater once a year to remove the mineral deposits and buildup from inside the tank. To completely flush the tank of old water and sediment: ^{[19]
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- Disconnect your water heater from power and let the tank cool.
- Shut off the water supply valve going into the top of your tank.
- Connect a garden hose to the bottom drain valve on the water heater tank. Place the other end of the hose in a drain.
- Open the drain valve to remove the water from the tank.
- Turn on the water supply valve when the tank is almost empty to rinse out residual buildup.
Testing the pressure relief valve helps clear out any sediment that’s built up inside and ensures that pressure can escape if the water gets too hot. Simply place a bucket underneath the tube connected to the valve. Then, open the valve at the top of your water heater and leave it open for about 30 seconds. After that, close the relief valve. ^{[20]
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Unscrew the anode rod from the top of your hot water heater, and pull it straight out. If the rod looks clean and smooth, then reinstall it. If you see buildup or corrosion on the rod, then replace it with a new one. ^{[21]
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Turn your water heater off and disconnect it from power while you’re working. Remove the panels covering the electrical elements of the thermostats and heating elements. Use a screwdriver to tighten all of the screws and wires to ensure they have a solid connection. ^{[22]
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5
Test the thermostats with a multimeter. Set your multimeter to ohms to test for continuity. Turn off power to your water heater. Then, uncover the panels over the thermostats and disconnect the wires. Hold the multimeter probes against the thermostat screws to test them. ^{[23]
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- If your thermostats are working properly, then the continuity reading will be 0 ohms.

Section 4 of 5:

Safety Precautions Before Making Repairs

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1
Disconnect your water heater from power sources. Calame mentions that it’s good practice with any water heater to turn off the power before you take it apart or make any repairs. This protects you from getting shocked or injured while you’re working.
- For electric water heaters, use the power switch to turn it off, and then switch off the breaker in the electrical box.
- For gas water heaters, find the gas supply valve on the intake pipe near the water heater. Turn the valve perpendicular to the pipe to shut off the gas. Then, turn off the water heater’s breaker at your electrical box.
2
Open the pressure relief valve on the tank. The pressure relief valve usually looks like a small handle or knob near the top of your water heater. Lift the handle or rotate the knob to open the valve and release some of the pressure from inside the tank so you’re less likely to get sprayed by water during repairs. ^{[24]
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- Once you open the relief valve, watch out for hot water coming out of the water heater’s bottom valve.
3
Drain the water from your water heater. Draining your water heater prevents any of the hot water from splashing or scalding you while you’re troubleshooting the problem. To quickly drain the heater:
- Turn off the power and water supply valves
- Connect a hose to the bottom valve on your water heater. Place the other end of the hose into a drain.
- Turn the bottom valve counterclockwise to open it and start draining the tank.
- Once the tank drains, turn on the pressure relief valve to flush out the last bit of water.

Section 5 of 5:

When to Call a Pro

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Contact a plumber if you’re not confident doing repairs on your own. Troubleshooting the problem may be a little tricky if you’re not familiar with how water heaters work. Rather than trying to take apart the unit yourself, hire a professional to:
- Diagnose the issue if you’re unable to find it
- Find a leak
- Fix or replace a burner
- Repair a faulty gas line
- Replace the water heater entirely

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Double-check your water heater’s warranty to see if damage or faulty parts are still covered. If you still have coverage, a technician may be able to repair your water heater at no cost.

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Warnings

Make sure your water heater is disconnected from power whenever you’re working on it so you don’t get shocked.

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Be careful when you drain or open your water heater because the water inside can be extremely hot.

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What to Do if Your Water Heater Is Not Working Properly

What to Do if Your Water Heater Isn’t Working

Steps

Causes & Fixes for a Hot Water Heater Not Working

Other Common Water Heater Issues

Preventing Issues with Regular Maintenance

Safety Precautions Before Making Repairs

When to Call a Pro

Expert Q&A

Video

Tips

Warnings

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References

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