In today’s world, hot water is readily available in most of the homes and to gain access to it has become as simple as turning on the faucet. While it was considered a luxury only a few decades ago, it has now become a necessity for every household.

While water heaters have become an essential component in modern homes, it might potentially be extremely dangerous if not maintained properly. Well, we are not suggesting that your water heater is a ticking time bomb. Generally, both electric, as well as gas water heaters, are safe to use, especially when you maintain the system properly. In addition, most models are equipped with monitoring alarms and sensors that come to aid in accidents like fires and carbon monoxide leaks.

However, if you’re concerned regarding the state of your water heater or have noticed something doubtful, always contact a professional technician. While some people are interested in doing things on their own, it is advisable to leave the water heater maintenance to professionals for safety.

In this article, we will take a closer look into the water heater explosions and its potential causes. Furthermore, we will also go through all the signs, which may be indicating possibilities of water heater explosion and measures to prevent your water heater from an explosion.

Table of Contents

How Does Water Heaters Work?

Before getting into any other topics regarding water heaters and its explosion, first, we need to understand how the unit operates.

Basically, there are two types of water heaters — gas water heaters and electric water heaters. Although all the water heating systems have similar working principles, different models and brands operate in a slightly different way.

In general, all water heaters operate by using some kind of combustion to heat the water inside the tank.

Gas water heaters generally use a burner to heat the water inside the storage tank. Similarly, an electric water heater uses coils as the heating element. Most water heaters these days come with a digital dial for temperature adjustment. Once the water inside the storage tank reaches the maximum temperature, the burner automatically turns off.

For most water heating systems, the manufacturer recommends a water temperature setting no higher than 120 degrees Fahrenheit.

What Does Each Part Do?

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To simplify how a water heater operates, here we provide you the breakdown of each part of the unit and explanation regarding what it does.

  • Copper Piping: A water heater uses two copper pipings — an outgoing hot water pipe and an incoming cold water pipe. Both these copper pipers are located on top of the water tank.
    Dip Tube: The dip tube, which is located inside the tank, is used to distribute cold water at the bottom of the holding tank. Note: if the dip tube of your water heater breaks or deteriorates, it will not heat the water properly.
  • Anode Rod: An anode rod basically protects the dip tube and reduces the mineral buildup inside the tank. Although this rod smells like sulphur, please do not remove it from the water heater. This rod attracts corrosive minerals that can eventually deteriorate your water tank, and improve its life.
  • Drain Valve: Located at the bottom of the tank, a drain valve is used to empty the storage tank. Sometimes, mineral buildup can cause a banging or knocking sound inside the tank. Although it does not sound like much, it is essential to open the drain valve to flush the water and release the mineral buildup in every few years. This helps to reduce the chances of rust and leaks inside the tank and increase its lifespan.
  • Pressure Relief Valve: Located at the top of the water tank, the pressure relief valve is a safety device that relieves pressure and balances the system when the pressure or heat becomes too high for the tank to handle. If you notice this valve leaking, you should consider replacing it immediately.
  • Discharge Tube: A discharge tube is generally another safety device that helps to prevent burns and injuries by stopping the scalding water from spraying out. It needs to be installed on the pressure relief valve and should be placed about six inches above the floor.

What Causes a Water Heater to Explode?

To be honest, water heaters are usually safe and are verified under various safety standards. However, if not looked after properly, these essential systems can turn into a ticking bomb, waiting to explode.

But what exactly causes the water heater to explode?

Basically, water heaters can explode if the temperature of the thermostat is set too high or if the pressure relief valve malfunctions. This can happen with both gas water heaters as well as electric water heaters. The most common reason for the malfunction of the pressure relief valve is the blockade in the pipe or the failure in releasing the pressure inside the tank.

When the water heats up, it actually turns into a gas. And, when both the pressure and heat becomes too much for the water tank to withstand, it tries to release the pressure through a pressure relief valve. If the value is broken or blocked and is not able to release the pressure, the increasing pressure eventually results in an explosion.

The damage caused by the explosion can be massive. Although it is highly unlikely for water heaters to explode, they operate in a similar way to a rocket, when they do.

Therefore, you must always check the pressure relief valve of your system to ensure that the valve is operating in proper condition. If you are not sure about its condition and notice something doubtful, hire a professional technician to inspect the system.

To prevent such casualty, the best precaution you can take is to set the temperature of your water heater no higher than the manufacturer’s suggested setting.

Warning Signs Before Water Heater Explosion

In most cases, a water heater explosion does not happen out of nowhere. There are always certain signs and signals that the system gives to warn you regarding the condition of your water heater.

As soon as you notice something unusual or hear strange sounds coming out from the water heater, we recommend you consult a professional technician to inspect the system. So, here are some of the most common warning signs that might potentially be telling you that your water heater is about to explode.

Steady Popping Noise

While in operation, a water heater usually makes a slight bit of noise. However, if the noise grows over time and starts to sound like a popcorn machine, it might be the right time for a check-up. Usually, it is caused due to the sediment build-up on the bottom of the storage tank. In this case, the water heating unit might be working twice as hard to heat the water. If not addressed in time, this might cause the tank to deteriorate overtime and might be more susceptible to burst.

Gas Smell

If you own a gas water heater, you probably know the potential danger of a gas leak. If you smell gas anywhere near your water heater, you should immediately turn off the water heater and call the technician for help. Usually, the smell might be similar to the odor of rotten eggs. If you notice anything as such, the risk of the explosion might be high.

Open Relief Valve

One of the most important features of any water heater is the T&P valve. This valve opens and releases water to minimize the pressure inside the tank. If you notice your relief valve opening once or twice, it might not be a big deal. However, if you notice that the valve of your unit is constantly open, it might indicate the pressure inside the tank is extremely high, which might eventually end up bursting.

Rusty-Looking Water

One of the worst enemies of a water heater is rust and corrosion. However, modern heaters are equipped with an anode rod that is used to attract the molecules responsible for rust. Although the anode rod can last for several years, it might be damaged if you do not maintain the system properly. If this happens, the tank is likely to leak and might even burst in the worst cases.

Therefore, if you notice rusty-looking water, it might be due to the deterioration of your anode rod. In this case, you should immediately consult professionals, and might get your water heater serviced or replaced.

Tank Leaks

Leaks are usually the most terrible thing that can happen to a water tank. It is obvious that nobody would want to wake up and see a pool of water beneath the water tank. However, leaks in your system might also indicate something worse. It is best to repair the leaks as soon as you notice it, not only to prevent more damage but also to safeguard against potential explosion.

Of course, it is also possible for a new water heater to explode! However, that’s highly unlikely until the system is not installed correctly.

How to Prevent Water Heater Explosion

The best way to prevent a water heater explosion is by properly maintaining the unit or replacing the entire system as soon as you notice any leaks or other issues. Also, there are a few steps you can take to maintain your water heater, and none of these require a plumber.

Even if your water heater does not indicate any signs or symptoms, it should be thoroughly checked at least once a year and maintained routinely to keep the heater in the best possible condition.

Here are a few things you need to maintain to prevent a water heater explosion:

T&P Valve Check

One of the most crucial parts of any water heater is the temperature and pressure relief valve (T&P valve). This valve is usually located at the top of the unit or high on the side. You must check this valve at least twice a year to get optimum performance.

To test the condition of the T&P valve, put a bucket under the valve, and flip the switch of the valve for approximately five seconds. Make sure to wear clothes that can protect you against any splashed scalding water as some water might be released during the test. If you notice that the valve is malfunctioning or if there’s anything faulty, consider replacing the valve immediately.

Temperature Check

While it might be tempting to keep the thermostat at the highest possible settings, doing so might actually shorten the life of the T&P valve and your water heater. Generally, it is recommended that you keep your thermostat to 120 degrees. However, if you want to go higher than that, we recommend you to stick up to 140 degrees maximum.

Higher temperature creates more pressure in the system, which might force the T&P valve to activate frequently. This might wear out the valve causing the water to leak all over the floor.

Anode Rod Check

An Anode rod is basically a sacrificial rod that attracts rust and corrosive agents from the water. Over time, there’s a high chance that the rod rusts and decomposes as it protects the water heater’s walls. If not replaced on time, the walls of the tank might also start to rust.

In such a case, a tank explosion is more likely to occur as the walls of the tanks begin to thin out and rupture. It is significant that you check the anode rod at least once every year and replace it immediately if necessary. Also, note that there are different types of anode rods available in the market. So, make sure to buy the rod that suits your water heater the best.

Gas Check

Obviously, the risk of explosion is always higher with gas water heaters. If you smell gas or sulfur near a gas water heater, turn the heater down immediately. If you do not turn off the unit on time, it might lead to an explosion or a fire hazard.

It is always better to take the help of professionals if you’ve noticed a gas leakage or faulty gas control valve. Never turn the case back on until you take care of the gas leakage. If the connection of the gas control valve is at fault, it is easily replaceable as the controls are located outside the tank.

In addition, it is also essential to note that defective water heaters may also release carbon monoxide. Although odorless, this gas can cause serious injuries such as dizziness and difficulty in breathing. Therefore, we also recommend that you keep a carbon monoxide detector next to the water heater to warn you about the escaping CO2 gas.

Regular Flushing

As you all know, sediments and minerals are common to build up inside the water tank. Too much sediment can increase the pressure inside the tank and might also cause the water temperature to be uneven. Therefore, flushing out the tank once every year can significantly reduce the danger of tank explosion and allow the anode rod to operate more efficiently. Not that the process of flushing the system might take a bit longer than other maintenance.

Install the Unit Above Floor Level

While this may not always be possible, it is recommended that you install the water heater at least 18 inches above floor level, especially if you own a gas water heater. It is because flammable liquids such as paint thinner, brake cleaner, gasoline, lacquer, or contact cement might be stored in the same location.

If such flammable material is stored near the water heater, the vapors of such liquids might reach the gas control valve, which might result in an explosion. As most flammable vapors only float close to the ground, installing the water heater above floor level will significantly reduce the risk of explosion.


While it is highly unlikely for a water heater to explode, you should never neglect the possibility of such accidents. There are several reasons why a water heater might explode and breakthrough your roof. If you notice something strange and doubtful in your water heating system, we recommend that you contact a professional technician and have him/her inspect the entire unit. Also, it is advisable to check the unit regularly and maintain it accordingly to prevent any serious damage. Cheers!

(Last Updated on June 11, 2020 by Sadrish Dabadi)

Nina Howell is a Rewenable Energy researcher and consultant based out of Houston, Texas Area. She earned her Master's Degree in Energy and Earth Resources from Austin Jackson School of Geosciences in 2010, and a Bachelor's Degree in Environmental Science from State University of New York College of Environmental Science and Forestry in 2008. Nina has been working in the energy sector since 2011. She worked as an Energy Supply Analyst from 2011 to 2017 in Bounce Energy and then as a Research and Energy Consultant at GE Renewable Energy from March 2017 to February 2020 . Nina is a mom of 2 beautiful children who are joy to her life. She strongly believes in eco-friendly living and is vocal about renewable energy, environmental issues, water crisis, and sustainable living.