Can an Electric Water Heater Explode

There are some dangers with Electric Water Heaters and even some horror stories that I have heard in recent years. Warnings are listed on the tags that are found on every Heater that I have seen. Some list scalding and the risk of explosion. But Can an Electric Water Heater explode?

Yes, If the Temperature is set or gets too high:
It Increases Rust & Sediment buildup inside the Tank, making the inside tank walls thin & vulnerable to high pressure while corroding anodes that help control the Pressure Relief Valve that keeps the heater from overheating and possibly exploding.

There are advantages to using an Electric Water Heater and the main one being cost. They are inexpensive to install, are safe, and can last fairly long with some minor maintenance and replacement parts.

Dangers of Electric Water Heaters


If you have the following problems, your water heater could be at risk of exploding.

  • Sediment build-up
  • Rust corroding the Sacrificial Anode and Tank
  • Too much Internal Pressure

Sediment Buildup

Over time sediment is built up from minerals that are found in your drinking water and collected at the bottom of your Electric Hot Water Heater Tank. That layer of sediment will insulate the water from the burner and the water heater will need to run longer to bring it up to temperature, causing it to overheat and ultimately deteriorate the tank.

The water in the tank will start making popping and knocking noises. This noise is water trapped under the sediment bubbling up, trying to escape the sediment layer. It’s like how trapped boiling water pushes up a pot’s top. The only way to stop this from happening is to flush out the tank. With the proper maintenance and a few procedures, you can prevent any ruptures or explosions that may take place over the lives of your water heater and add years to its life and service.

Rust Corrosion

Your water tank is made of steel (iron) and will corrode over time from the water inside that will making the inside of the tank rust. The Sacrificial Rod located inside the tank will act as protection for the liner of the tank. The 3-5 foot rod will rust out in place preventing the metal in the water heater tank to deteriorate for a while.

Once the rod deteriorates then the water tank starts to rust and that is when the water heater is in danger of exploding. Inspecting the anode rod once every two years and at least once annually after the warranty is expired is recommended.  You’ll probably change the anode rod once every 4-5 years sooner still if you have a water softener.

Too Much Internal Water Pressure

If too much water pressure is built up inside the water tank, it will burst and spring a leak. The higher the water pressure then the more power is produced inside the vessel. Your water heater is equipped with a TP Valve a Pressure Temperature Relief Valve that works when the pressure inside is relieved to the outside of the tank for this exact reason, to prevent an explosion from happening. The Water Heater could become a missile or bomb if the pressure is not relieved.

If the valve keeps opening and closing then it will most likely start to fail. If you decide to turn up the temperature then the pressure will be built up in the tank. With higher temperatures and too much water pressure, rust and sediment built up inside the tank, then the Water Heater is at risk of an explosion.  


How An Electric Water Heater Works


In an Electric Water Heater, a Thermostat is mounted on the inside water tank that holds the water and senses the temperature that is present normally to 120-125 degrees. Once that temperature falls below the desired setting it will trigger a switch to a heating element found mostly on the top of the tank and another on the bottom called Dual Elements. The switch will allow electricity to flow to the elements firing them up to heat the water. This will happen until the pre-set temperature reaches where it is desired and then shuts the electricity to the Elements off.

The heating element is submerged in the water of the tank and heats up in the same way that an electric stove burner works, by passing electricity through a resistant material and converting energy into heat. When the thermostat senses that the water has reached the correct temperature, it shuts off the power to the element. Pretty simple operation.


How To Troubleshoot an Electric Water Heater


The water heater has very few components in the appliance itself. The tank is where you will find most of the difficulty and maintenance. Your heater will most likely run every day of the week unless you are on vacation. There are a few easy ways to identify and fix a problem. Most have to do with leaking pipes or joints that can be easily fixed. If handle valves are leaking you can easily tighten them without any major work.

If the water is too hot or too cold you may just have to make a small adjustment to the thermostat. If there is no hot water then check the breaker that might have tripped. If there is not enough hot water, simply it could be the location where the water heater is working from. There are insulated jackets that can wrap around your water heater if it’s working from the garage or a cold room.

The most common problem is a common reset on the Electric Water Heater.

The water heater’s reset switch, which is usually a red button on the upper thermostat of an electric water heater (you will need to remove the small panel to access it).

If the button is lit up, it means the switch tripped and needs to be reset. You reset the electric water heater reset button by pushing that red button. There may be two on your heater. If you press the reset button and there is no click then you may have a bad part like the thermostat itself in the lower or upper part of the heater. Normally they will reset and you will be back to normal operation. If this continues then you may need a plumber.

On most appliances sold today, there are tags that are easily accessible to the owner on the door of the appliance or somewhere on the rear. If there is an access door you will find it when you open the door.  The tag will have the manufacturer’s serial number and the date it was made. Regular maintenance and occasional eyeball will be enough to maintain and spot any problems.

Electric Water Heaters are built to last 10-12 years and require very little maintenance.

An annual flush to the heater’s vessel will wash out any sediment that has collected inside from the supply water that is delivered constantly.


 How To Flush an Electric Water Heater


To buy a new Pressure Relief Valve is up to you (you can use the old one if it doesn’t leak but for 10 bucks you might get a few more years without working on it ever again). Flush the system and test or change the Pressure Relief Valve.

  1. First, test the pressure-relief valve located on the top or side of the water heater. This valve opens automatically if the pressure inside the tank gets too high.
  2. Place a bucket below the discharge pipe on your hot water heater tank and gently lift the lever on the pressure
  3. Do a relief valve to test it. If the valve doesn’t release water when you lift the lever, replace the valve sold at home centers and hardware stores. Replacement is simple; turn off the water, drain the tank, unscrew the discharge pipe and then unscrew the old valve. Wrap the threads of the new valve with sealant tape and screw it in. If your valve is several years old and has never been tested, it might leak after you test it. In that case, replace the valve.
  4. Close the shutoff valve on the cold water supply pipe that feeds the water heater.
  5. Then turn on the hot water at any faucet to release the pressure inside the heater’s tank. Leave the faucet on until you finish your work.
  6. Assuming you have an electric heater, turn off the power at the main panel. With a gas heater, turn the gas control dial to “off.”
  7. Drain the tank to flush out dirt and sediments that have settled at the bottom of the tank. That Sediment buildup will shorten the life of your water heater and adds to your energy bill by reducing its efficiency. Draining 2 or 3 gallons of water is usually enough to flush out sediments, but always let the water flow until you no longer see particles in the bucket. Open the drain valve slowly and let the water run until it’s clear and free of sediments.
  8. To restart the water heater, open the shutoff valve and let the hot water run at any faucet to purge air from the system. Usually, the fastest way to purge the system of air is to bleed from the farthest point.
  9. Then turn on the power or relight the pilot.
  10. Set your water heater’s dial to 120 degrees F. If the dial doesn’t have numbers, check the water temperature with a cooking thermometer.

Sometimes higher temperatures are needed to compensate for less hot water but if you do increase the temperature on the heater that will help create more sentiment. Most people’s first reaction is to turn up the thermostat on the heater to get more hot water.  So it snowballs. The higher temperatures just create more sediment buildup and the risk of explosion, and scalding injuries. Try and flush the tank clean.

The Environment Around the Water Heater

I’ve seen a lot of water heaters that are located in easily accessible areas like the garages that are connected to the house or the basement in the house. The problem with both of these locations is that if the tanks were to rupture and water comes out the damage would be minimal.

If you do install the tank in one of these places, make sure you set the tank on a wooden piece of plywood to separate the bottom of the tank and the top of the floor from having long prolonged contact with each other.   

The hardness of the water and wet environment along with metal and paint from the tank deteriorate the metal faster. So put a wooden coaster under the tank. You’ll thank me in 10 years when the same tank “keeps on ticking”


Signs Your Water Heater is Going to Explode


  • Leaks only get worse and if you are seeing some around the Teflon connections, you got to get on it pronto Bud!
  • Noise is sometimes an indicator. If you hear your water heater – loud cracks and pops for instance – it may be an indication that the interaction between the heating elements and the inside heater has mineral build-up on them that comes from the supply of potable water.
  • Warm water but not hot water can be an indication of your heating element burning out. Adjust your thermostat to make sure the temperature is set between 120 to 140 degrees, anything lower could provide warm but not hot water. If you have to do it more than once then chances are you need to perform maintenance on the system.
  • Metallic Smell & Taste-When you turn on the hot water, it’s cloudy and has a metallic smell and taste to it. This is a sign that the water heater is breaking down, with grit and flakes from the inner tank combined with your water supply.
  • Traces of Sand or Sediment- These pieces of Sediment could be flaking from the breakdown of the inner jacket on the tank.
  • Sudden No Hot Water You turn on the hot water to find no hot water. This can be caused by one of two things. One, your pilot light is out or the circuit breaker has tripped. Or your hot water heater has reached its useful life and has gone to Hot Water Heaven.
  • Your hot water has turned Red, the Rust colored.
  • Life expectancy is up to 10-12 years. You’ll find a yellow or red tag on your heater that contains when it was manufactured and when the last time the heater was serviced.

The two most common water heater malfunctions a homeowner may encounters require replacing either (or sometimes both) a thermostat or a heating element. Most standard electric water heaters have two thermostats and two elements.

Gas water heaters that have gas burners to heat the water are set to temperature. Electric water heaters rely on a pair of upper and lower metal heating elements to heat the water. In an electric water heater, the bottom heating element does the work, since it is at the bottom of the tank that cold water is delivered into. You can buy the tune-up kit for the water heater right here through Amazon. You can add the Heating Elements when you flush the system on the Annual maintenance procedure.


Water Heater Element Voltage Test


The Elements in the Electric Water Heater are run by either thermostat. One on top and one on the bottom. Each one heats the water to a set temperature normally 120-130 degrees. A burnt-out thermostat is a normal problem in heaters and can break if one of the elements breaks. Either way, a bad Heating Element or Thermostat can lead to a higher risk of an explosion or rupture of the Hot water Tank if the temperatures are not working in a proper range.

There is a risk of Electric Water Heaters rupturing and even exploding even if the heater is well maintained or new. The risk will increase, the older the tank is and the less care you gave it during its lifetime. The damage to your house could be minimal to devastating.

Depending upon the problem, you can get different symptoms. For example, a sulfur or rotten egg smell coming from outside the tank is most certainly a gas leak, while a sulfur smell coming from your faucets suggests a colony of microbes in the tank. Brown or yellow water can also suggest rust or sediment buildup, as well as pings and pop sounds in the tanks or pipes.

Water Heater Explosion Warning Signs

Testing the Pressure Relief Valve on the tank near the top is a relatively simple task a few times a year could help avert a water tank from exploding. Watch out for scalding hot water. Wear some protective clothing and hold a bucket underneath the valve. Flip the valve switches up for 5 seconds. It should release water and if it shows signs of failure then get rid of it and replace it. It’s easy to check out this article on How to change a TPR Valve on an Electric Water Heater.

Temperature Check- If you have to adjust the thermostat to get the hot water you need then there could be another problem. Set the heater at 130 degrees and turn it up no more than 140 degrees. Hotter temperatures can create more pressure that forces the TPR Valve to open and close which will end up breaking it. Hotter water temperatures also create more sediment that can snowball in the tank causing blockages and more problems.

Anode System Check-The anode is a sacrificial rod that attracts corrosive agents in your tank’s water. As a result, the rod rusts and decomposes instead of the water heater’s walls. They work the same on any type of metal to protect other metals A tank explosion is possible when the walls of the tank get too thin and eventually rupture.

An Anode Every year, check the anode rod in the water heater, and if it is almost or completely corroded then it is time to replace it with a new one. Anode rods tend to last around three to five years. On some models, it’s also possible to install a second anode rod to your water heater to extend its life as well.
You should check the anode yearly and replace it as necessary. Note that there are several types of anode rods, so you may wish to invest in a rod that best suits your household needs.

Annual Flushing of the tank will keep the inside of the water heater as clean as it could be of sediment that will destroy anything that it lays up against, including the wall of the tank that again gets too thin and can cause pressure in the tank to rupture it and explode.

Keep the Water Heater Tank up above contact with the floor. This keeps water, paints, and chemicals from prolonged contact with the lower bottom of the tank. I use a piece of 3/4 inch plywood to level off the tank and keep the bottom dr. *Gas Water Heater is specifically installed 18 inches above the floor level because of code enforcement laws that recognize that vapors from chemicals can cause explosions when left open too close to the Gas Control Valve. Locate, Remove, and Replace  Anode Rod.


Old & New Anode Rods                                                                           

  1. -Turn Off Circuit Breaker and Cut Power
  2. Locate the Anode Rod located on the top side of the unit.
  3. Drain Tank-Connect a garden hose to the drain outlet near the bottom of the heater. Extend the hose to an outside location or a plumbing drain that is lower than the tank. Drain the tank only until the water level is beneath the place where the anode rod is located.
  4. Remove Anode Rod-The anode rod can be removed with a boxed end wrench or socket. If it will not turn using a wrench, use a socket and breaker bar. Tightening the anode rod slightly will help break the threads loose, making removal easier. Never use penetrating fluids such as Liquid Wrench on water heater components, as these fluids could contaminate your hot water supply.
  5. Install new Anode Rod-If you have limited clearance, you can find a flexible anode rod. With the threads on the new anode rod pointed downward, wrap them with the plumber’s Teflon white tape or lightly coat them with joint compound. Insert the new rod and turn the component clockwise until it cannot be turned by hand, then tighten it another 1/2 turn using your socket wrench. Do not allow the water heater to turn or twist while doing so.
  6. Restore Water and Power-Make sure the drain is closed, and turn on the cold water supply. Open the same hot water valve as you used to drain the tank and allow it to flow until all air has been removed from the tank.

Electric Water Heaters are reliable and can last a dozen or so years if you know how to spot oncoming problems and perform some simple tasks to keep your hot water coming.

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