When a hot water heater isn’t working, it’s normal to think that only the pros can fix it. But many problems, including leaks, inadequate hot water, or rust-colored water can be fixed by yourself.

In some cases, it’s just a matter of adjusting a setting or pressing a reset button. Some other common causes for a hot water heater not working include a faulty healing element, sediment buildup, and even a bad thermostat.

Of course, you’ll want resolution quickly because a malfunctioning water heater can mean being unable to do chores such as the dishes or laundry. Sometimes, you may not be able to bathe either.

Here are 10 common water heater problems and how to fix them.

WARNING

Electric water heaters are high-voltage (240-volt). Before checking the electrical parts of a water heater, shut off the power to the heater by turning off the appropriate breaker in the electric service panel (breaker box). Also, test all wires in the water heater with a non-contact voltage tester to confirm the power is off before touching the wires.

10 Common Water Heater Problems and How to Fix Them

No Hot Water

A water heater that produces no hot water might not be getting power, might have a tripped limit switch, or might have one or more failed heating elements.

Here is how you can diagnose the cause of your lack of hot water:

• First, check the water heater’s circuit breaker in the service panel to make sure it hasn’t tripped. If the breaker has tripped off, rock it to the OFF position, and then back to ON.
• If the heater’s breaker did not trip off, reset the high-temperature limit on the heater. To do so, turn off the power to the water heater in the service panel. Next, remove the access panel. Press the high-temperature reset button, which is usually red.

Inadequate Hot Water

If your water heater is producing hot water but not enough of it, the heater could be too small to meet the household’s hot water demand. If this is the case, here are some solutions:

• Limit the length of showers.
• Install low-flow shower heads.
• Spread out dishwashing and laundry to different times of the day.

Tip

A water heater should be able to supply 75-percent of its total capacity as hot water. For example, a 40-gallon water heater is properly sized for a demand of 30 gallons. 

However, if your unit is not undersized or it suddenly produces less hot water than before, one or both of its heating elements might have failed. For example, a constant supply of lukewarm water during a shower could mean a defective upper heating element. Hot water that runs out quickly could mean a defective lower heating element. In either case, you must call a professional to replace the heating elements or the water heater.

Water Temperature Is Too Hot

Too much hot water typically means that one or both of the hot water heater’s thermostats are set too high.

To fix this:

• First, turn off the power to the water heater in the service panel.
• Next, remove the access panel and check that the heat setting on both thermostats is no more than 120F°.
• Adjust to the desired setting by turning the set screw with a flathead screwdriver.

Water Heater Is Leaking

Water heater leaks are often caused by leaking valves and plumbing connections. If you touch the water and it is warm or hot, it is likely the result of a leaking outlet pipe.

To repair leaking valves or plumbing connections, simply do the following:

• First, inspect the water heater for loose inlet or outlet pipes.
• If you find loose connections, simply tighten these with a wrench. This will fix the leak.

Rust-Colored Water or Bad Odor

When brown, yellow, or red-tinted water flows from faucets, the water heater tank may be internally corroded. When water comes out smelling like rotten eggs, the hot water heater tank could contain bacteria.¹

For tinted water:

• Have a plumber replace the anode rod in the water heater tank. An anode rod is a metal rod in the center of the water heater that corrodes more easily than the tank itself. Oxygen, which is corrosive, is attracted more easily to the anode rod than to the water heater.

WARNING

Bacteria in potable water, or Legionella, can be fatal if ingested. Consult a professional if you suspect this.²

Tank Making Noises

Noises coming from the water heater that sound like a low rumbling, popping, or high-pitched whine could mean that the water in the tank is boiling. Sediment build-up in the bottom of the tank can cause the bottom of the tank to overheat and the water to boil.

To resolve this issue:

• First, make sure to turn off the power and water supply to the water heater.
• Second, completely drain the water heater of the water and sediment and then fill it again.
• Attach the inner-threaded end of a garden hose to the valve at the bottom of the water heater, with the other end located outside.
• Open both the temperature pressure relief valve at the top and the drain valve at the bottom.
• After water and sediment have fully drained out, close the bottom valve and the upper-pressure relief valve, and then remove the hose.
• Turn on the power and water again.

Leaking Cold Water From an Inlet

If a pool of water develops at the top of the water heater, the cause may be a leaking cold water inlet. This inlet is located at the top of the water heater. Tightening this connection will often stop the water leakage.

After first turning off the water supply to the water heater, tighten the inlet connection with a wrench by turning clockwise. Turn the water supply on again, dry off the top of the water heater, and observe for leakage.

Damaged Pressure Relief Valve

The temperature pressure relief valve on the side of the hot water heater may develop a slow leak. In many cases, you can replace the valve by yourself. To do so, follow the below steps:

1. Turn off the electricity and cold water supply to the water heater.
2. Drain water and pressure by opening the valve with a bucket placed below the plastic relief valve drain pipe.
3. Unscrew the pressure relief valve with a pipe wrench.
4. Screw the valve into the water heater, being sure to use Teflon plumber’s tape.
5. Attach the plastic relief valve drain pipe.

Water Heater Is Leaking From the Sides

Water leaking from the sides of the water heater can indicate a tank that is leaking due to corrosion or damage. This type of water leak flows from specific areas such as holes or cracks.

Any tank that has damage or corrosion on the tank itself should be replaced. Tanks cannot be safely repaired.

While waiting for a new water heater, prevent damage to the home by turning off the power and the water supply to the water heater, and then completely draining the tank.

Condensation on the Water Heater

Water heaters that appear to be leaking may actually be giving off water condensation. Water condensation will be widespread across the tank’s outside, rather than localized as with cracks or inlet leaks. Water heater condensation usually does not indicate a problem with the water heater, though excessive water can damage the flooring.

To fix excess condensation:

• Try setting the temperature at 120F° or even lower to 115F°.
• Hire a plumber to disconnect the water heater and add a drain pan underneath to catch drips.

When to Call a Professional

In some cases, you will not be able to fix your hot water heater without the help of a professional. Sometimes, you may even need to replace your hot water heater. Situations where you must call a professional to fix or replace include:

• Tanks with damage or corrosion on the tank itself (you will need to replace the entire tank).
• Cases of tinted water or foul odor.
• Suspected bacteria in your water.
• Certain instances of inadequate hot water.

The hot water heater may have a warranty that partially covers professional repairs. Check the paperwork that came with the water heater or consult the plate on the heater’s side with the model and serial number. 

These numbers detail the year the tank was made and can help you determine whether the tank has a prorated warranty that might offer a new tank or parts, either free of charge or at a discount. Warranties typically do not cover labor.

Maintenance Tips to Prevent Water Heater Problems

Of course, you shouldn’t wait until something goes wrong to maintain your hot water heater! Regular maintenance is necessary and can help prevent problems in the first place. Some examples of hot water heater maintenance include:

• Drain the water heater at least once a year.
• Insulate the pipes.
• Have the water heater inspected regularly.
• Keep the temperature at 120F° or lower.
• Test the temperature pressure relief valve once or twice a year, with a bucket placed under the outlet tube to catch water.
• Have a plumber replace the anode rod about every five years.

FAQ

• How do I reset my hot water heater?A hot water heater will have a reset button. Typically red, you can locate your reset button directly next to one of the thermostats (most likely the top one). To reset, push the reset button and this should resolve the issue within an hour. Just be sure to avoid touching any wires when doing so.
• What is the most common cause of water heater failure?The most common cause of water heater failure is due to a slow leak or sudden burst.
• Is a broken water heater an emergency?It will depend on the nature of the issue. If there is a slow leak, it is okay to wait. As well, a lack of hot water isn’t necessarily an emergency but rather a nuisance. However, major leaks should be addressed immediately to avoid water damage and other issues.
• How long does it take for a hot water heater to reset?After pushing the reset button, you should have normal use of your hot water heater again within a few hours.