5 Common Water Heater Problems and How to Fix Them

Posted by
John Woodard on April 28, 2023

Water heaters are essential for the everyday cleanliness of your home. Showers, baths, dishwashers, washing machines, and faucets all utilize hot water to keep you and your home safe from bacteria, dirt, and grime. When water heaters fail to function properly, dishes and clothes cannot be cleaned properly, and you suffer the inconvenience of a cold shower. Fortunately, many water heater problems can be fixed easily, either by yourself or by a licensed professional. Below you can find information on common problems water heaters face and how to fix them.

Common water heater problems and how to troubleshoot them

Water heater problems can be caused by electrical or gas problems, failures in water heater elements, or faulty pipes or valves.

1.  Water heater is not heating water.

A lack of hot water can be caused by a variety of issues. In electric water heaters, a power loss or heating element failure can cause water to no longer heat in the tank. In gas water heaters, a faulty gas connection, a bad pilot light, or a bad burner can cause no water to heat.

Electric water heater

If you own an electric water heater and you do not have hot water, check the breaker to check if it has tripped unexpectedly. If it has, reset the circuit, and your water heater should continue to operate normally. If there were no power disturbances, the heating element may be at fault. In this case, the element must either be repaired or replaced by a professional.

Gas water heater

If you own a gas water heater and do not have hot water, check that the pilot light is on. If the temperature has dropped low enough, the lines may be frozen. In this case, the lines must be thawed before water can be heated. If water is not heating but the pilot light is on and the lines are not frozen, you will need a professional to assess your heater for problems.

2.  Hot water has a foul odor.

A foul smell coming from your hot water typically means that the water has been sitting in your water heater for too long. To ensure that the smell is caused by the water heater, run cold water to check if it possesses the same odor as the hot water. If only the hot water contains a foul odor, the problem lies within the water heater. In this case, bacteria were allowed to grow as water sat at a constant temperature in the heater for an extended period. If the odor persists or is present elsewhere, hydrogen sulfide may be to blame. If you are unsure of the cause of the odor, it is worth performing a water test.

To combat hot water with a foul odor, the heater must be flushed. All water heaters should be flushed at least once annually to prevent the buildup of sediment, minerals, and bacteria. Flushing reduces the chances of bacteria infesting a water heater, even when water has been sitting in the tank for a long time.

How to flush a water heater

  1. Shut off the water heater. For a gas water heater, set the thermostat to the “Pilot” setting. For an electric heater, turn off the power to the heater at the fuse box.
  2. Close the cold-water valve. This is located at the top of the tank.
  3. Allow the heater to sit. This prevents the risk of burns while emptying the tank. Allow the tank to sit for at least two hours before proceeding.
  4. Connect a garden hose to the drain valve. If the water is cool, you can drain it into a drain or your lawn. Warm or hot water should not be drained onto your lawn or plants.
  5. Turn on a hot water faucet in your home. This prevents pressure from building up in your lines during the draining process.
  6. Open the drain valve. Allow the tank to completely empty. Take note of any concerning symptoms in your tank, such as leaks or any abnormal sounds.
  7. Turn on the cold water. Allow the cold water to run through the hose until the water appears clear. Shut the cold water off once the water is clear. This rinses the tank, removing any bacteria that may remain on the heater’s walls.
  8. Close the drain valve and remove the hose. Once the tank has been sufficiently flushed, the drain valve should be closed so the tank can fill.
  9. Fill the tank. Once the drain valve is closed and the hose is disconnected, turn the cold water on to let the tank fill. The hot water faucet in your home should remain open during this step. Once the hot water faucet in your home is running without any fluctuations in flow, the water heater is full.
  10. Turn on the water heater. For gas heaters, change the thermostat to its normal settings. For electric heaters, turn the power to the heater on at the fuse box. The heater will begin heating the water.

3.  Limescale is building up in water heater.

water heater limescale

Limescale buildup is the result of hard water flowing through pipes and appliances. The minerals in hard water coat the edges of plumbing fixtures, eventually developing into thick layers that slow down water flow. Water heaters are the most susceptible appliance in the home to limescale. When water heats in a water heater, some of it evaporates, leading to a higher concentration of minerals in the water that is left. Limescale in a water heater threatens damage to the heating element, and it also increases the amount of energy used to heat water. The three most common symptoms of limescale buildup in water heaters are:

  • Banging or crackling sounds coming from the heater.
  • Rust-colored water with a foul odor.
  • Heating element failure.

How to reduce limescale buildup in water heaters

The best way to reduce limescale buildup in a water heater is to treat the water before it reaches the tank. This treatment can be performed by a water softener or a water heater filter. Once appropriate pretreatment is in place, the tank can be cleaned to eliminate the limescale already in the system. A water heater free of limescale will heat water more efficiently than a system suffering from limescale, and the heating element is at less risk of damage than a scaled heater.

Learn more: How to descale a water heater | What is a water heater filter?

4.  Water heater is leaking.

water heater leak

A leaking water heater can be caused by numerous problems, the most common including:

  • Pressure valve failure. A water heater’s relief valve, also known as the temperature and pressure release valve, can fail if it is old, incorrectly installed, or loose. If the valve is installed incorrectly or broken, the pressure inside the tank must be lowered until a working valve can be incorporated into the tank.
  • Sediment buildup. Sediment buildup in a water heater collects at the bottom of the tank. If the tank is not regularly flushed, this sediment eventually causes cracks to form in the tank’s wall and floor. The best ways to prevent sediment buildup in a water heater are annual flushing or appropriate pre-treatment, such as a whole-house water filtration system.

Learn more: What is a whole-house filter and how does it work?

  • Loose drain valve. A water heater’s drain valve is used anytime the tank is emptied. Over time, this valve may eventually degrade or loosen, causing water to leak. If tightening the drain valve does not cure the leak, the valve likely needs to be replaced.
  • Old anode rod. The anode rod is the component in a water heater that prevents corrosion to the tank. It attracts the mineral content in water, preventing the rest of the tank from suffering the effects of contact with these minerals. When the anode rod has collected enough minerals, it is no longer effective, and the rest of the tank is put at risk. An old anode rod can be replaced to help prevent tank corrosion in the future.
  • Loose inlet and outlet connections. Loose inlet and outlet connections are the most desirable form of water heater leak because they are the simplest to fix. As a water heater ages, the connections that intake and output water may loosen, causing water to leak out of these fixtures. When these leaks occur, the outlets must simply be tightened, and the leaks should be resolved.
  • Small or missing thermal expansion tank. A water heater thermal expansion tank, alongside the pressure release valve, protects water heaters from excessive pressure buildup. If the expansion tank is too small for the water heater, pressure can rise too high, causing leaks to spring from the system. Older homes may not contain a thermal expansion tank alongside the water heater. In these cases, an expansion tank can be installed relatively inexpensively. A thermal expansion tank provides security, water damage protection, and leak prevention while taking up little space.

Learn more: What is a water heater thermal expansion tank?

5.  Water is too hot or cold.

Water from a water heater that is too hot or not hot enough may be the result of a broken thermostat or heating element, but it can also be caused by an incorrect setting. The factory temperature for water heaters is 120 degrees Fahrenheit, but this may be too hot or not hot enough for some users. If your water is too cold, turn the thermostat to 140 degrees, and wait about one hour before testing the water again. If the water is still too cold, there is likely an issue with the thermostat or heating element. Likewise, if your water is too hot, turn the temperature on the thermostat down and test if the water has changed in temperature. If the temperature remains constant, you will need to contact a professional to diagnose and resolve your problem.



If you have any additional questions, please do not hesitate to contact us.

No comments yet.
Leave a comment