Can a Water Heater Explode? Yes, it Can. Find Out How to Prevent it Here!

Warning! Water heaters explosions are a reality.

Heating your domestic water eats up almost to 20% of your home energy costs annually, so your water heater must be looked after. It's an essential part of your family's life and well worth ensuring it's looked after regularly.

If your water heater bursts and floods your home, that is in the top 20% of water damage issues, according to a report from the Insurance Institute for Business and Home Safety (IBHS).

They report the average claim was just under $4500. But you can relax, can't you? Your water heating system is well maintained and serviced, right?

No? Then you should read on; it could save from serious injury or even kill you.

All it takes are a few simple things that will prevent you from becoming a statistic because flooding is potentially the least of your concerns.

All you need to do is visit your water heater occasionally.

I know it's a pain. It's like visiting relatives you can never find the inclination to visit with. You know you should, but we always find something better to do, don't we?

Try not to put it off.

Explosions can kill

Explosion sign - danger

See this label? It's fitted to water heaters, and it's a serious warning. It's not put there for amusement. Water heater explosions are a reality and not fun at all. The effects of an exploding water heater outdo simple flooding by a considerable margin, of the scale, in fact. 

Explosions can cause serious injury or even kill someone in your family, but they are always devastating. Think about this; is your insurance still going to cover something caused by lack of maintenance? Perhaps not. One thing's for sure; it will cost way more than the average $4500 claim if you need to build a new home.

OK, enough of the scary stuff. You've visited your out-of-sight-out-of-mind relative, sorry, your trusty water heater, so what do you do now?

How to prevent your water heater exploding

Gas tank-type water heaterGas tank-type water heater

Over time, natural residue from your water drops to your heater's tank base, which creates a layer that separates the water from the power source, often a gas burner. This will cause your burner to work harder and longer to bring your water up to temperature. As the layer thickens over time, it can cause the system to overheat and damage the tank and much more besides.

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Listen to the sounds it makes

On your visit, listen to the sounds your water heater making. It could be a sign that something is wrong. If you hear bursts of popping or bumping sounds, it's water trapped under the layer of residue expanding and escaping into the main tank. These may be attractive sounds if you're boiling a kettle on a camping stove in the great outdoors, but in your water heater, they are signs that all is not well.

Prevent tank residue once a year

The tank needs to be cleared of residue at least once a year, especially if you live in a hard water area. Hard water contains minerals that become sediment. Some newer water heaters have a self-clean system, so you won't need to clean it as often, perhaps once every three years.

Water heater tank types

Steel has been used extensively in water heaters, and it has a natural inclination to rust when it comes in contact with water. Glass-lined and stainless steel tanks have been gaining popularity.

Although in areas where the water supply contains high levels of chorine, stainless steel is also at risk unless you use a very high-grade material. It comes in a wide range of grades, but the ones most commonly used in water heaters are 304, 316L, 316Ti, and 444. The higher the grade, the more expensive it is, but the longer it lasts.

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Check the water heater anode as recommended

The other item that needs attention is the anode, which is a long rod inside the tank that pulls rust away from the steel wall of the tank. It's usually made from a magnesium alloy and acts as an anode to the water tank wall, which acts as the cathode. It is referred to as a 'Sacrificial anode' because, over time, it is destroyed instead of the water tank, so it prolongs the life of the water heater tank, but only if it's in good shape.

Stainless steel water heaters don't use an anode, but they are still fitted to glass-lined tanks to prevent damage to the steel. They should be checked every two to three years and are easy to check and replace if necessary.

Prevent explosions by checking the temperature and pressure relief valve

The last critical item is the temperature and pressure relief valve (TPR valve), which is there to protect you and your family from the extreme pressure inside the tank and a life-threatening explosion. It opens automatically should the pressure in your water tank exceeds the limit set by the manufacturer. The relief valve and your thermostat work in harmony to keep you safe.

If the valve fails to open when the pressure in your water-heater tank rises above the acceptable level, there is a danger of an explosion. Think of a balloon being over-inflated; it eventually ruptures and explodes. It's the same thing here if there's too much pressure, and it's unable to release, something has to give.

The reason the pressure relief valve may fail could be one of many. Manufactured equipment fails; it's a fact. It can be jammed open or closed by a build-up of minerals and other debris that flows into your heater in freshwater intake.

That simple blockage could cause flooding if it jams open. But if it jams closed, it could be deadly. It needs to be checked regularly to make sure it opens readily, allows water to flow then closes again tightly.

Preventing explosions is not rocket science

It's not rocket science, but if it blocks solid, it could cause your water heater to become a rocket.

Exploding water heaters tend not to go off like a bomb but much more like a propelled rocket, straight upwards and through your floors and roof. One example traveled over 439 Feet into the air before returning to earth, which is further than some recent large-scale rockets managed to achieve!

The number of exploding water heaters is relatively small, thankfully almost as small as the households who do basic maintenance on their water heater each year. You check your car is safe for your family by ensuring it's maintained and checked for apparent faults, so why not your water heater?

YouTube video: Mythbusters Water Heater Explosion

Which types of water heaters are  more liable to explode?

Storage tank water heaters 

These are the most common type of water heaters used in homes today. These units are perfectly safe, provided they are regularly maintained and checked. They should be professionally serviced once a year for safety.

Tank-type heaters are designed with a water storage tank that can store over 100 gallons of water, and as they are prone to high-pressure situations, they include a safety pressure relief valve.

Tankless water heaters

Tankless water heaters are usually smaller because they have no large storage tank attached and heat water on demand using gas or electricity. These units are very safe, but as with the tank-type models, there were some models in the past recalled by the CSPC.

Point of use water heaters (POU)

POU water heaters work in the same way as tankless, where the water is heated on demand as it passes the heating source, or as tank-type water heaters, which are equipped with the storage tank. A typical installation would be a single-point water heater at a sink, for example.

Larger, more powerful units are available for small homes or bathrooms with a limited requirement for hot water. They do have the potential for an explosion if not appropriately maintained.

Heat pump water heaters

Heat pumps for heating water (hybrids) can be stand-alone units fitted on top of a 20 – 80-gallon storage tank. These typically have backup heating elements installed so that if the water temperature isn't high enough, you can boost the temperature.

Heat pump water heaters can also work in conjunction with a standard, existing storage water heater. The same cautions apply as the tank is fitted with a pressure relief valve for safety, and if it fails, there is a risk of explosion. Basic maintenance and an annual professional check by a registered plumber are essential.

Solar water heaters

Solar water heaters can only provide around 60% of the hot water used in an average house.

They work in tandem with a conventional water heater by pre-heating the water. It subsequently reduces the total amount of energy you use to heat your water as the water entering your water heater is much warmer than from the regular water supply. 

The conventional water heater they work with carries the same risk of explosion if not properly maintained and serviced annually by a professional plumber.


Heating your domestic water supply uses up to 20% of your home energy costs annually, so it's an essential element of your expenditure and worth ensuring it's looked after and working efficiently. Sadly it tends to be a poor relation when it comes to maintenance, even though it works hard to keep us all supplied with hot water 24/7.

Most of us have a water heater of some type in our home and are an actively ignored part of our lives until they break down; of course, then it's different. The critical thing is they can and do explode, which is a pretty dramatic way to get attention; however, a few basic maintenance routines will keep you in hot water and out of it at the same time.

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