Common water heater problems & DIY fixes

Whether you’re dealing with a water heater leak repair or troubleshooting temperature issues, knowing how to perform basic repairs can save time and money. Let’s break down the most common problems in water heaters so you can confidently get your unit back up to speed.

If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Water heater problems & why they happen

Understanding the reason behind water heater issues is the first step in making repairs. Here are some of the most common problems, along with typical causes.

Leaks

A water heater leak is one of the most frequent issues homeowners face. Leaks can occur due to:

• Loose connections between the water heater and the supply pipes
• Corrosion or rust on the inside of the tank, which can cause small holes
• A faulty pressure relief valve can cause water to escape from the tank

How to fix it

• Use a wrench to check and tighten any loose connections between the heater and supply pipes. Be cautious not to overtighten anything, as this could cause damage.
• If you determine that the pressure relief valve is the culprit, you can easily replace it. You’ll need to turn off the water heater, drain a portion of the tank, and swap the old valve with a new one. Be sure to follow your manufacturer’s instructions for this process.
• If you inspect the tank and find that it’s rusted or corroded, you’ll need to replace the entire water heater.

No hot water

A water heater that’s not producing hot water can have one of many issues, depending on whether you have a gas or electric model.

On a gas water heater:

• If the pilot light has gone out, the burner won’t ignite to heat the water.
• A faulty thermocouple can prevent the pilot light from staying lit.
• A problem with the gas supply could prevent hot water. The gas valve must be open and functioning properly.

On an electric water heater:

• If the circuit breaker has tripped, the heating elements won’t work.
• A burned-out heating element won’t heat the water.
• If the thermostat fails, it won’t send voltage to the elements to heat the water.

How to fix it

On a gas unit: 

Relight the pilot light by following the manufacturer’s instructions. If it won’t stay lit, test and replace the thermocouple if needed. Be sure to check the gas supply as well to make sure there are no leaks or other problems.

On an electric unit: 

Reset the circuit breaker and use a multimeter to test the heating elements. If the heating elements are faulty, replace them. If the elements are good, then the thermostat is likely faulty.

Water is too hot

If your water heater produces excessively hot water, it may have a faulty thermostat or temperature setting.

How to fix it

• Make sure that the temperature setting isn’t above 120°F (49°C), which is the recommended safe level.
• If the thermostat isn’t responding to temperature adjustments, it may need to be replaced. To do this, you’ll need to disconnect the heater from the outlet, remove the thermostat and install a new one.

Strange noises

Loud rumbling or popping noises coming from your water heater are usually caused by sediment buildup inside the tank.

How to fix it

• Remove sediment buildup by flushing the tank. You’ll need to drain it completely and refill it with water.
• If your water heater frequently develops sediment or you live in an area with hard water, consider using a water softener to reduce mineral deposits.

Pilot light won’t stay lit (gas models)

A pilot light that repeatedly goes out on a gas water heater typically signals a problem with the thermocouple, gas supply, or venting system.

How to fix it

• Replace the thermocouple if it’s malfunctioning. A bad thermocouple can cause the pilot light to go out frequently. 
• Check the gas supply. Make sure the gas valve is fully open and that there aren’t any blockages in the supply line.
• Inspect the venting system and remove any obstructions. Insufficient airflow can cause the pilot light to go out.

How to maintain your water heater to prevent future problems

Taking the time to perform regular maintenance can prevent many common issues with water heaters — and save you a ton of time and money in the long run. Here are some tips to help you make the most of your unit.

• Flush the tank at least once a year to remove sediment buildup that can reduce efficiency and cause damage.
• Inspect and test the pressure relief valve every 3-4 months to make sure it’s functioning properly.
• Keep an eye on the anode rod, which helps prevent corrosion inside the tank. Check it every year and replace it if it’s worn out.
• Keep the thermostat set to 120°F to prevent overheating and scalding.

Frequently asked questions

Get answers to some of the most common questions about water heaters.

Why is my water heater only warm, not hot?

This could be caused by a broken dip tube or a malfunctioning thermostat or heating element(s).

What do I do if my water heater isn’t staying hot?

You may need to flush the tank, replace the heating elements, or see if your water heater is big enough for your home’s needs.

Additional information

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